From nobody Mon Jun 8 21:54:57 2026 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE7C93DD507 for ; Tue, 26 May 2026 10:20:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790859; cv=pass; b=JO56SO02Q6b7SfyNPUmiJP5mzbtVKCxckMNOk10ohAd2zJ6P37eu1/ag+Ft9IcfEL4gyXxbIVWNIDXurXbQW7jZccNj44zwkJWDgkeHcgMP6hd2YOw1a5aBbeVBm9amgoZIbOHHBJOrluBh6xdtsybbOQRKdd/tiAZ2tjCTIYmg= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790859; c=relaxed/simple; bh=h8Kv+rO8uzzaQ7Der2lsiEQZ1CQa+2F0miPOLA3TiZU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=G2uivgCSocXHkjyl7Zn25TETO5sNhz9oNaKKlNJwyNBENbvGdJcqtIFH9CVrMj0kVFimR6hBEOSe7cJHUdmmeEe1VtNMXBsxXo9ANf9EwIwP+ZVcJfs6000Ee6bG/AupJBwsemxoFqljj7640R+KGSpNR+7LwplJfA3F4lTKLOk= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=hLtLdx32; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="hLtLdx32" ARC-Seal: i=1; a=rsa-sha256; t=1779790830; cv=none; d=zohomail.com; s=zohoarc; b=bULlnrUpghyMlkYSwltA4oqL51zCVVwdtktyDKrMonCdS7IAMffQ4aOUfXiwSfWcoaqrhUUFlYAilVFsaITHOpUvITlQGgXAQA/FtPv2WuGjDRahCtgsne/RCMgXHPQI+Il+PRrUsRHG/GQrnjGZjqJjVoEkdWUslbrCM5B2qqg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790830; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=kWggu7MDEm92UFWOQVSGSXE74pC8cqPPYzngY7bmbL4=; b=YAtz6VaxYEIKLtl5Kys8PLuUUSOHsYopzwz9AieKAITdRvnMJQq1htAq83wflbcCL3AGFOGvscAfbigVdYSbrCGHCExhwKH5TE/RxTXpWQhNMsODjY69aTcyJZUwQElk2xQv87zcMsqmfC4vK8JBnW5cOm/4clEC5CTWkgJ85EY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790830; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=kWggu7MDEm92UFWOQVSGSXE74pC8cqPPYzngY7bmbL4=; b=hLtLdx329Zvc5Db9fX5SklzZpJpDDwOneW34My05GSpggiT69Y5t3EWf7niYtwbs WsNVSvSpzbfX1odQcaypY3ef0A7eawnX3k6uq3Ynw2HjEn9b42pKDK9nY8ythkxaD6W NMiu216CG8c2jYe6qebyZWCeJO9NEjz0PvKNauls= Received: by mx.zohomail.com with SMTPS id 17797908282201022.0314136280366; Tue, 26 May 2026 03:20:28 -0700 (PDT) From: Nicolas Frattaroli Date: Tue, 26 May 2026 12:19:57 +0200 Subject: [PATCH v3 1/4] drm/scdc-helper: Don't use ssize_t return type for scdc_read/write Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260526-scdc-link-health-v3-1-59e4a4aaead1@collabora.com> References: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> In-Reply-To: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.15.2 drm_scdc_read and drm_scdc_write, both of which are only used within drm_scdc_helper (although exported), use a ssize_t as their return type. This would make sense if they returned the number of bytes read/written on success, and negative errno otherwise. However, they return 0 on success. Demote them to "int" as their return type, in order to avoid needlessly using 64 bits when less suffices. No functional change. Signed-off-by: Nicolas Frattaroli Reviewed-by: Luca Ceresoli --- drivers/gpu/drm/display/drm_scdc_helper.c | 8 ++++---- include/drm/display/drm_scdc_helper.h | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/display/drm_scdc_helper.c b/drivers/gpu/drm/di= splay/drm_scdc_helper.c index df878aad4a36..8403f2390ab6 100644 --- a/drivers/gpu/drm/display/drm_scdc_helper.c +++ b/drivers/gpu/drm/display/drm_scdc_helper.c @@ -67,8 +67,8 @@ * Returns: * 0 on success, negative error code on failure. */ -ssize_t drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, - size_t size) +int drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, + size_t size) { int ret; struct i2c_msg msgs[2] =3D { @@ -107,8 +107,8 @@ EXPORT_SYMBOL(drm_scdc_read); * Returns: * 0 on success, negative error code on failure. */ -ssize_t drm_scdc_write(struct i2c_adapter *adapter, u8 offset, - const void *buffer, size_t size) +int drm_scdc_write(struct i2c_adapter *adapter, u8 offset, const void *buf= fer, + size_t size) { struct i2c_msg msg =3D { .addr =3D SCDC_I2C_SLAVE_ADDRESS, diff --git a/include/drm/display/drm_scdc_helper.h b/include/drm/display/dr= m_scdc_helper.h index 34600476a1b9..e9ccaeba56dd 100644 --- a/include/drm/display/drm_scdc_helper.h +++ b/include/drm/display/drm_scdc_helper.h @@ -31,10 +31,10 @@ struct drm_connector; struct i2c_adapter; =20 -ssize_t drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, - size_t size); -ssize_t drm_scdc_write(struct i2c_adapter *adapter, u8 offset, - const void *buffer, size_t size); +int drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, + size_t size); +int drm_scdc_write(struct i2c_adapter *adapter, u8 offset, const void *buf= fer, + size_t size); =20 /** * drm_scdc_readb - read a single byte from SCDC --=20 2.54.0 From nobody Mon Jun 8 21:54:57 2026 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22F233DD522 for ; Tue, 26 May 2026 10:20:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790859; cv=pass; b=Ai1A8neXONbVLcrCAq+w4E/RiyeHNj5m1XhnE1X1aBneNy1vVeKfLXFpm1MZkJbPJJ8bao1txXpeEcyTboopFwiRp7VNzHG/BliA9A+QHg/r2PF2DXzLPC69CBlHBYXaVhRfzUa17AEmIhgPghzvhZjk/kjaJU4UUQYUISW7ZZ8= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790859; c=relaxed/simple; bh=JJqGLi1l0SmxjaYNCnHwdsnHQqnJTubyCEiFZbk1zwc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=CSiFT8K9P5sFu67eJB0yyxianuXBPloxwNybJFjerGGr1WVLpJJtfqxIui9cv5gd5I4OuY0jdnmu8/FkSPWHeqSqa3V3wAKivJ8Znxbn9jWHy0o7qYYawE4KDxCThGVaQuUlZLYNbAJ8LUXM+EG7OtADPfzlLg1Puee6p9I4mkk= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=WYWIVROg; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="WYWIVROg" ARC-Seal: i=1; a=rsa-sha256; t=1779790834; cv=none; d=zohomail.com; s=zohoarc; b=gm/nz4rq3CNA157uu5PV8d68RTipQ9lxdYFNJq1XHyoXHZuoRvGQ+GaZzzrJrIb9mUR7lu4xOGfGpRN5DpBVopvbJyGa+rCiY9kr8eGsv4JDmm2YlQkUaoQnuM+p/UMDEn0+AaPIhl6iBtHYPxlSJ2e4vyZQnvUvQGgVozqsQHw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790834; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=qhVyDrEkh0VyrdpSxpgzW+jQc35AEiGuV7N0DLWHrFw=; b=R3OwsReiGJ11U8nSzQnacYqksiBjxa4Qcag60qs1Rl2f36fKkrCRA1cTVu0YABI3o+8hQqoWwWZSMY+RwsU7AcpPV8UiwDE7uhfQtOSeZ17l7lKX3U9IwLRhFsSjxzdp0IafJqvnbVHVep2XkdQmo+Nsic1WRdzzkeIsFq4OZIw= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790834; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=qhVyDrEkh0VyrdpSxpgzW+jQc35AEiGuV7N0DLWHrFw=; b=WYWIVROgBJRwxFCjpLzt8dqDdYkkjgtFFLxv8WqP5pgEBA77Pd1gEQK3gbqX2XON JgtwlKBGlPdUe9wyS3cbiDDy1tKqq4dIgh/umgBtCHScfpkD3ELlN9tY4u1qXrgwOaN RRA+Jv4faDASGtWv/s3DzHOK8/BRbKzpwjdv5Ad4= Received: by mx.zohomail.com with SMTPS id 1779790832782324.5541276177297; Tue, 26 May 2026 03:20:32 -0700 (PDT) From: Nicolas Frattaroli Date: Tue, 26 May 2026 12:19:58 +0200 Subject: [PATCH v3 2/4] drm/scdc-helper: Add scdc_status debugfs entry Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260526-scdc-link-health-v3-2-59e4a4aaead1@collabora.com> References: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> In-Reply-To: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli , Daniel Stone X-Mailer: b4 0.15.2 SCDC provides status information on the current display link. At the very least, it may be useful to expose this info through debugfs. Add a debugfs entry for it under the connector, which displays a few more details parsed out of the SCDC registers. A new drm_scdc_debugfs_init function can be called by the connector implementation to initialise the debugfs file. Reviewed-by: Daniel Stone Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/display/drm_scdc_helper.c | 228 ++++++++++++++++++++++++++= ++++ include/drm/display/drm_scdc_helper.h | 56 ++++++++ 2 files changed, 284 insertions(+) diff --git a/drivers/gpu/drm/display/drm_scdc_helper.c b/drivers/gpu/drm/di= splay/drm_scdc_helper.c index 8403f2390ab6..75a59c6fc7a5 100644 --- a/drivers/gpu/drm/display/drm_scdc_helper.c +++ b/drivers/gpu/drm/display/drm_scdc_helper.c @@ -24,11 +24,14 @@ #include #include #include +#include #include +#include =20 #include #include #include +#include #include =20 /** @@ -55,6 +58,11 @@ =20 #define SCDC_I2C_SLAVE_ADDRESS 0x54 =20 +struct scdc_debugfs_priv { + struct drm_connector *connector; + struct drm_scdc_state state; +}; + /** * drm_scdc_read - read a block of data from SCDC * @adapter: I2C controller @@ -276,3 +284,223 @@ bool drm_scdc_set_high_tmds_clock_ratio(struct drm_co= nnector *connector, return true; } EXPORT_SYMBOL(drm_scdc_set_high_tmds_clock_ratio); + +/** + * drm_scdc_read_status0_flags - Read SCDC "Status Flags" Register + * @connector: pointer to &struct drm_connector to issue the scdc request = on + * @flags: pointer to the caller's &struct drm_scdc_status_flags to output= to + * + * Reads the SCDC Status Flags 0 register, and outputs its contents to the + * destination @flags. Contents of @flags.status0 is only valid if function + * returns 0. + * + * Returns: %0 on success, negative errno on error. + */ +int drm_scdc_read_status0_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags) +{ + int ret; + + ret =3D drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_STATUS_UPDATE= ); + if (ret) + return ret; + + return drm_scdc_readb(connector->ddc, SCDC_STATUS_FLAGS_0, &flags->status= 0.data); +} +EXPORT_SYMBOL(drm_scdc_read_status0_flags); + +/** + * drm_scdc_read_error_counters - Read and clear SCDC error counters + * @connector: pointer to &struct drm_connector to issue the scdc request = on + * @counter: Caller's u16 array with 3 elements to write the counter value= s into + * + * Read the SCDC channel error counters. If the count of channel *n* is va= lid, + * write it into counter[n]. Otherwise, set counter[n] to 0. Reads all cou= nters + * in one read chunk, then clears every counter, as is mandated. + * + * Returns: %0 on success, negative errno on error. + */ +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[3]) +{ + u8 buf[7] =3D { 0 }; + int ret; + u8 sum =3D 0; + int i; + + ret =3D drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_CED_UPDATE); + if (ret) + return ret; + + ret =3D drm_scdc_read(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(b= uf)); + if (ret) + return ret; + + /* + * Verify the "checksum", i.e. sum up everything including the checksum + * register as a wrapping unsigned 8-bit addition and verify it's 0. + */ + for (i =3D 0; i < ARRAY_SIZE(buf); i++) + sum =3D wrapping_add(u8, sum, buf[i]); + + if (sum) + return -EPROTO; + + for (i =3D 0; i < ARRAY_SIZE(buf) - 1; i +=3D 2) { + if (buf[i + 1] & SCDC_CHANNEL_VALID) + counter[i / 2] =3D buf[i] | (buf[i + 1] & ~SCDC_CHANNEL_VALID) << 8; + else + counter[i / 2] =3D 0; + + buf[i] =3D 0; + buf[i + 1] =3D 0; + } + buf[ARRAY_SIZE(buf) - 1] =3D 0; + + return drm_scdc_write(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(b= uf)); +} +EXPORT_SYMBOL(drm_scdc_read_error_counters); + +/** + * drm_scdc_read_state - Update state from SCDC + * @connector: pointer to a &struct drm_connector on which to operate on + * @state: pointer to a &struct drm_scdc_state to fill + * + * Reads update flags from SCDC, and updates the parts of @state that SCDC + * claims have changed, as well as populating those where such a distincti= on + * can't be made. + * + * Returns: %0 on success, negative errno on failure. + */ +int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_s= tate *state) +{ + u8 upd_flags[2] =3D { 0 }; + struct i2c_adapter *ddc; + struct drm_scdc *scdc; + int ret; + u8 val; + + if (!state || !connector) + return -ENODEV; + + scdc =3D &connector->display_info.hdmi.scdc; + ddc =3D connector->ddc; + + if (!scdc->supported) + return -EOPNOTSUPP; + + ret =3D drm_scdc_readb(ddc, SCDC_TMDS_CONFIG, &val); + if (ret) + return ret; + + state->scrambling_enabled =3D !!(val & SCDC_SCRAMBLING_ENABLE); + state->tmds_bclk_x40 =3D !!(val & SCDC_TMDS_BIT_CLOCK_RATIO_BY_40); + + state->scrambling_detected =3D drm_scdc_get_scrambling_status(connector); + + ret =3D drm_scdc_read(ddc, SCDC_UPDATE_0, &upd_flags, sizeof(upd_flags)); + if (ret) + return ret; + + if (upd_flags[0] & SCDC_STATUS_UPDATE) { + ret =3D drm_scdc_read_status0_flags(connector, &state->stf); + if (ret) + return ret; + } + + if (upd_flags[0] & SCDC_CED_UPDATE) { + ret =3D drm_scdc_read_error_counters(connector, state->error_count); + if (ret) + return ret; + } + + return 0; +} +EXPORT_SYMBOL(drm_scdc_read_state); + +#define scdc_print_str(_f, key, s) \ + (seq_printf((_f), "%-30s: %s\n", (key), (s))) +#define scdc_print_flag(_f, key, val) \ + (scdc_print_str((_f), (key), str_yes_no((val)))) +#define scdc_print_dec(_f, key, val) \ + (seq_printf((_f), "%-30s: %d\n", (key), (val))) + +static int scdc_status_show(struct seq_file *m, void *data) +{ + struct scdc_debugfs_priv *priv =3D m->private; + struct drm_scdc_state *st =3D &priv->state; + struct drm_connector *connector =3D priv->connector; + struct drm_scdc *scdc =3D &connector->display_info.hdmi.scdc; + int ret; + + drm_connector_get(connector); + + if (connector->status !=3D connector_status_connected) { + ret =3D -ENODEV; + goto err_conn_put; + } + + scdc_print_flag(m, "SCDC Supported", scdc->supported); + if (!scdc->supported) { + ret =3D 0; + goto err_conn_put; + } + + scdc_print_flag(m, "Sink Read Request Capable", scdc->read_request); + scdc_print_flag(m, "Scrambling Supported", scdc->scrambling.supported); + scdc_print_flag(m, "Low Rate Scrambling Supported", scdc->scrambling.low_= rates); + + ret =3D drm_scdc_read_state(connector, st); + drm_connector_put(connector); + if (ret) + return ret; + + scdc_print_flag(m, "Scrambling Enabled", st->scrambling_enabled); + scdc_print_flag(m, "Scrambling Detected", st->scrambling_detected); + + if (st->tmds_bclk_x40) + scdc_print_str(m, "TMDS Bit Clock Ratio", "1/40"); + else + scdc_print_str(m, "TMDS Bit Clock Ratio", "1/10"); + + scdc_print_flag(m, "Clock Detected", st->stf.status0.flags.clock_detected= ); + scdc_print_flag(m, "Channel 0 Locked", st->stf.status0.flags.ch0_locked); + scdc_print_flag(m, "Channel 1 Locked", st->stf.status0.flags.ch1_locked); + scdc_print_flag(m, "Channel 2 Locked", st->stf.status0.flags.ch2_locked); + + scdc_print_dec(m, "Channel 0 Errors", st->error_count[0]); + scdc_print_dec(m, "Channel 1 Errors", st->error_count[1]); + scdc_print_dec(m, "Channel 2 Errors", st->error_count[2]); + + return 0; + +err_conn_put: + drm_connector_put(connector); + + return ret; +} +DEFINE_SHOW_ATTRIBUTE(scdc_status); + +/** + * drm_scdc_debugfs_init - Initialize scdc files in connector debugfs + * @connector: pointer to &struct drm_connector to operate on + * @root: debugfs &struct dentry for the debugfs root of @connector + * + * Creates SCDC-related debugfs files for @connector. Must be called after + * @root is already created. + */ +void drm_scdc_debugfs_init(struct drm_connector *connector, struct dentry = *root) +{ + struct scdc_debugfs_priv *priv; + + if (!root || !connector) + return; + + priv =3D drmm_kzalloc(connector->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return; + + priv->connector =3D connector; + + debugfs_create_file("scdc_status", 0444, root, priv, &scdc_status_fops); +} +EXPORT_SYMBOL(drm_scdc_debugfs_init); diff --git a/include/drm/display/drm_scdc_helper.h b/include/drm/display/dr= m_scdc_helper.h index e9ccaeba56dd..c066c1158275 100644 --- a/include/drm/display/drm_scdc_helper.h +++ b/include/drm/display/drm_scdc_helper.h @@ -30,6 +30,55 @@ =20 struct drm_connector; struct i2c_adapter; +struct dentry; + +struct drm_scdc_status_flags { + /* Status Register 0 */ + union { + struct { + bool clock_detected : 1; + bool ch0_locked : 1; + bool ch1_locked : 1; + bool ch2_locked : 1; + bool rsvd_4 : 1; + bool rsvd_5 : 1; + bool rsvd_6 : 1; + bool rsvd_7 : 1; + } flags __packed; + u8 data; + } status0; + + /* Status Register 1 */ + union { + struct { + bool rsvd_0 : 1; + bool rsvd_1 : 1; + bool rsvd_2 : 1; + bool rsvd_3 : 1; + bool rsvd_4 : 1; + bool rsvd_5 : 1; + bool rsvd_6 : 1; + bool rsvd_7 : 1; + } flags __packed; + u8 data; + } status1; +}; + +struct drm_scdc_state { + /** @stf: contents of the status flag registers */ + struct drm_scdc_status_flags stf; + /** @scramling_enabled: true if TMDS scrambling is on */ + bool scrambling_enabled; + /** @scrambling_detected: true if the sink actually detected scrambling */ + bool scrambling_detected; + /** + * @tmds_bclk_x40: true if TMDS bit period is 1/40th of the TMDS + * clock period, false if it's 1/10th of the clock period. + */ + bool tmds_bclk_x40; + /** @error_count: character error counts for each channel */ + u16 error_count[3]; +}; =20 int drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, size_t size); @@ -77,4 +126,11 @@ bool drm_scdc_get_scrambling_status(struct drm_connecto= r *connector); bool drm_scdc_set_scrambling(struct drm_connector *connector, bool enable); bool drm_scdc_set_high_tmds_clock_ratio(struct drm_connector *connector, b= ool set); =20 +int drm_scdc_read_status0_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags); +int drm_scdc_read_state(struct drm_connector *connector, + struct drm_scdc_state *state); +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[3]); +void drm_scdc_debugfs_init(struct drm_connector *connector, struct dentry = *root); + #endif --=20 2.54.0 From nobody Mon Jun 8 21:54:57 2026 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 329053CE090 for ; Tue, 26 May 2026 10:21:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790866; cv=pass; b=gkgrl77FcTRoTP4OdXmNaj2GPV+eR3dbZnx4GdgVbzNHTfp87pGynwEwRQaw1vh7JNncn7N5neRPcllFyNS5XOmSKVHI5182hDNxgEUBtHf9pcFixRb1XYFAalcJ0yltIzUAruPMe3b376DeWE+2bvTbYyHKI6q5oH7/BmtuJ8s= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790866; c=relaxed/simple; bh=q4HlZ9WSVO+WZ9U/0wYuEnwNei+/abXYH8VbqS0GAmA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=s1pno+9yr+pJx5PyV0jx8yjqxsMvTyPXjq3sVO+X5BSQES+6GyfMMMgGAKXxSYZlHjBI/qzk7ubiqw/GDxAWBGkz54A072+qpvpFuZe9zznd1K6CjXrrsj4igj2tdlMb9O86tyuX/TLeZolLA9YcWnCYj7JCfK+omO2sN4UOC1M= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=VeYPYOIS; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="VeYPYOIS" ARC-Seal: i=1; a=rsa-sha256; t=1779790838; cv=none; d=zohomail.com; s=zohoarc; b=B2bVxBGWVXtTjLpfA8W7m7PQ9VYccztkQ7scO7MgCfB4hlxm0iBAJODyZ5NMc/B1+oovGKZEM0qS6FRl46Ag+bKowfM+0uWoniMD2jYWrPnZLY/3e8+qrWn1C1O7nxy1dtzplAswmsOPzkUUcy61dlAn1ZWrUP9Y/A+nFSGJN2g= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790838; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=cdWc2b35HtrgVA2bHer/iyZW49LqV21zJlNgFyYKm0Q=; b=LMfXZmibG4iMEZGJ5AJRqdpFWL4F1xd/qdT+gQWp5ZNj355ccEOEhweqTseR58isnPcC37fube1OU+VnevYU5wKDW9lo/n0mpkPrss3zE072uzy2ZlugZkliqRq1nTzWVBHd39/FKhqWWOblZr7rmAcnQkyZxMkkVCssn0ap6jU= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790838; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=cdWc2b35HtrgVA2bHer/iyZW49LqV21zJlNgFyYKm0Q=; b=VeYPYOIS58QS7rr4IcZFfe4nR8tqZ1c5bJ9hW7w/G2uKm/DFqtPn6qqQN8bfFY1r Vu/x04qKRCMphaI4UNLhffvpdZ1vfs3T5ABa0E5d0p7nUC6YkUd3AdR0xXk0lGKbmpC vHlCMK3i7Vkuu8F/C+9OWlsKkIwg4+LaFlqDFnO8= Received: by mx.zohomail.com with SMTPS id 1779790837253946.8468736801963; Tue, 26 May 2026 03:20:37 -0700 (PDT) From: Nicolas Frattaroli Date: Tue, 26 May 2026 12:19:59 +0200 Subject: [PATCH v3 3/4] drm/display: bridge_connector: init scdc debugfs for HDMI Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260526-scdc-link-health-v3-3-59e4a4aaead1@collabora.com> References: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> In-Reply-To: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli , Daniel Stone X-Mailer: b4 0.15.2 On drm_bridge_connectors that contain an HDMI bridge, initialise the SCDC debugfs entry under the connector's debugfs root. Reviewed-by: Daniel Stone Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/display/drm_bridge_connector.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/d= rm/display/drm_bridge_connector.c index 649969fca141..8c2c890bd95d 100644 --- a/drivers/gpu/drm/display/drm_bridge_connector.c +++ b/drivers/gpu/drm/display/drm_bridge_connector.c @@ -25,6 +25,7 @@ #include #include #include +#include =20 /** * DOC: overview @@ -263,6 +264,9 @@ static void drm_bridge_connector_debugfs_init(struct dr= m_connector *connector, if (bridge->funcs->debugfs_init) bridge->funcs->debugfs_init(bridge, root); } + + if (bridge_connector->bridge_hdmi) + drm_scdc_debugfs_init(connector, root); } =20 static void drm_bridge_connector_reset(struct drm_connector *connector) --=20 2.54.0 From nobody Mon Jun 8 21:54:57 2026 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9735F3DC4D3 for ; Tue, 26 May 2026 10:21:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790872; cv=pass; b=jkU9EnTL0u+XC7mixH0fUHj+158F3L+GVzXyPuwxBGWrB8jXvS/5/NZRtTeF3y2/nt/E0etbSVtbY51ESz8fTpYqmYmdBeMjEtf++ZbZ+Pk46CfVRF2Ja1t+cJGt3ybQFLIBmDVVVQniWF4fuM81X9FuQpcarrdTE940YoKUA9E= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779790872; c=relaxed/simple; bh=ov2gUXp49cpqYb2wdoV3ZM/vd0sgYyJvuP8Mz+l9AXI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Bo+GkrlephxOmV6nLsa4YiTDWGaNl5ESYZOr4bGyXz3iScuD5QmrgZSQIki7Eq5Ek9VPsx0ANjl07ecDv7/sfErei8QtapEUqe40Tn/Gki7sxRoQ9f0DhrTH2KsJ/wVrA4hpsPmyiFPYf0S6oMyOssgJ7qo8avX7450hFssRaPI= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=aXlxj9tz; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="aXlxj9tz" ARC-Seal: i=1; a=rsa-sha256; t=1779790844; cv=none; d=zohomail.com; s=zohoarc; b=ey6m8N7ArfNq2XH8DX8PPytfMh5yuFDb2twFWemCg5SgQPdzsInkHps0RHP8G9KWUKJXHit77RAAOdl4xjVQeMmddED/JSpX7Ewb1j4wPESNEMBZCYMijcTWf/wGvHI+A548zL0ljpCCwh8r31mJo0EYnL0SbXbrwHQ7B8jMRPk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790844; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=8Bw44yj8ihcngpOzwLFcKybQ58rRbVJiSI4XfPqPIcQ=; b=mn1tHh4Kt0ozLeVM5KKQP2zb4yYXM2ujZ5gmD0ouliBX/32+GImSCPA5e4DGzRJH77kMla41d00Sn75lLX0s80kNmdUoJvEBOSoENmvk0Vsn5vAyOW/jyHuUEZ6Bi4KON1+Gspx+f8IKzTPEJhbbOfzNHNALmPchSeDQSlryIvs= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790844; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=8Bw44yj8ihcngpOzwLFcKybQ58rRbVJiSI4XfPqPIcQ=; b=aXlxj9tz4V31K77CofN/w8J+i4aXO0W0RgIjcB2WGkZXoBRq8BaAxsO/q5l7Y26d Z/fgE6AluteCJiq/YXADUcQl5q9oehR/Mz13vog7DKQMZNTrfiHV2h2pjFie7aqmqod TykbPmPgvMAyhMeU+IGxtUGqk1p6Wz0cwQBnNlSY= Received: by mx.zohomail.com with SMTPS id 1779790841806739.2556066328924; Tue, 26 May 2026 03:20:41 -0700 (PDT) From: Nicolas Frattaroli Date: Tue, 26 May 2026 12:20:00 +0200 Subject: [PATCH v3 4/4] drm/scdc-helper: Implement parsing and printing HDMI 2.1 fields Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260526-scdc-link-health-v3-4-59e4a4aaead1@collabora.com> References: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> In-Reply-To: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.15.2 HDMI 2.1 redefines previously reserved fields in SCDC for various new uses. No version check needs to be performed, as an HDMI 2.0 sink's reserved SCDC fields are well-defined to be 0, and any zero-ness of these fields for an HDMI 2.0 sink is not a surprise for SCDC parsers for HDMI 2.1. Implement reading and outputting these fields over debugfs. Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/display/drm_scdc_helper.c | 154 ++++++++++++++++++++++++++= ---- include/drm/display/drm_scdc.h | 9 ++ include/drm/display/drm_scdc_helper.h | 85 ++++++++++++++--- 3 files changed, 218 insertions(+), 30 deletions(-) diff --git a/drivers/gpu/drm/display/drm_scdc_helper.c b/drivers/gpu/drm/di= splay/drm_scdc_helper.c index 75a59c6fc7a5..b5a866372b0f 100644 --- a/drivers/gpu/drm/display/drm_scdc_helper.c +++ b/drivers/gpu/drm/display/drm_scdc_helper.c @@ -21,6 +21,7 @@ * DEALINGS IN THE SOFTWARE. */ =20 +#include #include #include #include @@ -63,6 +64,38 @@ struct scdc_debugfs_priv { struct drm_scdc_state state; }; =20 +static __pure const char *drm_scdc_frl_rate_str(enum drm_scdc_frl_rate rat= e) +{ + switch (rate) { + case SCDC_FRL_RATE_OFF: + return "Off"; + case SCDC_FRL_RATE_3X3: + return "3 Gbit/s x 3 lanes"; + case SCDC_FRL_RATE_6X3: + return "6 Gbit/s x 3 lanes"; + case SCDC_FRL_RATE_6X4: + return "6 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_8X4: + return "8 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_10X4: + return "10 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_12X4: + return "12 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_RESV_7: + case SCDC_FRL_RATE_RESV_8: + case SCDC_FRL_RATE_RESV_9: + case SCDC_FRL_RATE_RESV_10: + case SCDC_FRL_RATE_RESV_11: + case SCDC_FRL_RATE_RESV_12: + case SCDC_FRL_RATE_RESV_13: + case SCDC_FRL_RATE_RESV_14: + case SCDC_FRL_RATE_RESV_15: + return "(Reserved)"; + default: + return NULL; + } +} + /** * drm_scdc_read - read a block of data from SCDC * @adapter: I2C controller @@ -309,10 +342,57 @@ int drm_scdc_read_status0_flags(struct drm_connector = *connector, } EXPORT_SYMBOL(drm_scdc_read_status0_flags); =20 +/** + * drm_scdc_read_status1_2_flags - Read SCDC "Status Flags" 1 and 2 Regist= ers + * @connector: pointer to &struct drm_connector to issue the scdc request = on + * @flags: pointer to the caller's &struct drm_scdc_status_flags to output= to + * + * Reads the SCDC Status Flags 1 and 2 registers, and outputs their conten= ts to + * the destination @flags. Contents of @flags.status1 and @flags.status2 a= re + * only valid if function returns 0. + * + * Returns 0 on success, negative errno on error. + */ +int drm_scdc_read_status1_2_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags) +{ + int ret; + + ret =3D drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_FLT_UPDATE); + if (ret) + return ret; + + ret =3D drm_scdc_readb(connector->ddc, SCDC_STATUS_FLAGS_1, &flags->statu= s1.data); + if (ret) + return ret; + + return drm_scdc_readb(connector->ddc, SCDC_STATUS_FLAGS_2, &flags->status= 2.data); +} +EXPORT_SYMBOL(drm_scdc_read_status1_2_flags); + +#define ERR_DET_OFF(x) ((x) - SCDC_ERR_DET_0_L) + +static int __pure scdc_err_cnt_buf_idx(unsigned int lane) +{ + switch (lane) { + case 0: + return ERR_DET_OFF(SCDC_ERR_DET_0_L); + case 1: + return ERR_DET_OFF(SCDC_ERR_DET_1_L); + case 2: + return ERR_DET_OFF(SCDC_ERR_DET_2_L); + case 3: + return ERR_DET_OFF(SCDC_ERR_DET_3_L); + default: + return -EINVAL; + } +} + /** * drm_scdc_read_error_counters - Read and clear SCDC error counters * @connector: pointer to &struct drm_connector to issue the scdc request = on - * @counter: Caller's u16 array with 3 elements to write the counter value= s into + * @counter: Caller's u16 array with 4 elements to write the counter value= s into + * @num_lanes: number of active lanes, either 3 or 4 * * Read the SCDC channel error counters. If the count of channel *n* is va= lid, * write it into counter[n]. Otherwise, set counter[n] to 0. Reads all cou= nters @@ -320,18 +400,31 @@ EXPORT_SYMBOL(drm_scdc_read_status0_flags); * * Returns: %0 on success, negative errno on error. */ -int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[3]) +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[4], + unsigned int num_lanes) { - u8 buf[7] =3D { 0 }; + unsigned int buf_sz; + u8 buf[9] =3D { 0 }; int ret; u8 sum =3D 0; - int i; + int i, idx; + + switch (num_lanes) { + case 3: + buf_sz =3D 7; + break; + case 4: + buf_sz =3D 9; + break; + default: + return -EINVAL; + } =20 ret =3D drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_CED_UPDATE); if (ret) return ret; =20 - ret =3D drm_scdc_read(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(b= uf)); + ret =3D drm_scdc_read(connector->ddc, SCDC_ERR_DET_0_L, buf, buf_sz); if (ret) return ret; =20 @@ -339,24 +432,23 @@ int drm_scdc_read_error_counters(struct drm_connector= *connector, u16 counter[3] * Verify the "checksum", i.e. sum up everything including the checksum * register as a wrapping unsigned 8-bit addition and verify it's 0. */ - for (i =3D 0; i < ARRAY_SIZE(buf); i++) + for (i =3D 0; i < buf_sz; i++) sum =3D wrapping_add(u8, sum, buf[i]); =20 if (sum) return -EPROTO; =20 - for (i =3D 0; i < ARRAY_SIZE(buf) - 1; i +=3D 2) { - if (buf[i + 1] & SCDC_CHANNEL_VALID) - counter[i / 2] =3D buf[i] | (buf[i + 1] & ~SCDC_CHANNEL_VALID) << 8; + for (i =3D 0; i < num_lanes; i++) { + idx =3D scdc_err_cnt_buf_idx(i); + if (buf[idx + 1] & SCDC_CHANNEL_VALID) + counter[i] =3D buf[idx] | (buf[idx + 1] & ~SCDC_CHANNEL_VALID) << 8; else - counter[i / 2] =3D 0; - - buf[i] =3D 0; - buf[i + 1] =3D 0; + counter[i] =3D 0; } - buf[ARRAY_SIZE(buf) - 1] =3D 0; =20 - return drm_scdc_write(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(b= uf)); + memset(buf, 0, buf_sz); + + return drm_scdc_write(connector->ddc, SCDC_ERR_DET_0_L, buf, buf_sz); } EXPORT_SYMBOL(drm_scdc_read_error_counters); =20 @@ -376,6 +468,7 @@ int drm_scdc_read_state(struct drm_connector *connector= , struct drm_scdc_state * u8 upd_flags[2] =3D { 0 }; struct i2c_adapter *ddc; struct drm_scdc *scdc; + int num_lanes; int ret; u8 val; =20 @@ -397,6 +490,19 @@ int drm_scdc_read_state(struct drm_connector *connecto= r, struct drm_scdc_state * =20 state->scrambling_detected =3D drm_scdc_get_scrambling_status(connector); =20 + ret =3D drm_scdc_readb(ddc, SCDC_CONFIG_1, &val); + if (ret) + return ret; + + state->rate =3D FIELD_GET(SCDC_FRL_RATE, val); + num_lanes =3D drm_scdc_num_frl_lanes(state->rate); + if (num_lanes < 0) + return num_lanes; + if (!num_lanes) + num_lanes =3D 3; + + state->ffe_levels =3D FIELD_GET(SCDC_FFE_LEVELS, val); + ret =3D drm_scdc_read(ddc, SCDC_UPDATE_0, &upd_flags, sizeof(upd_flags)); if (ret) return ret; @@ -407,8 +513,15 @@ int drm_scdc_read_state(struct drm_connector *connecto= r, struct drm_scdc_state * return ret; } =20 + if (upd_flags[0] & SCDC_FLT_UPDATE) { + ret =3D drm_scdc_read_status1_2_flags(connector, &state->stf); + if (ret) + return ret; + } + if (upd_flags[0] & SCDC_CED_UPDATE) { - ret =3D drm_scdc_read_error_counters(connector, state->error_count); + ret =3D drm_scdc_read_error_counters(connector, state->error_count, + num_lanes); if (ret) return ret; } @@ -456,6 +569,8 @@ static int scdc_status_show(struct seq_file *m, void *d= ata) =20 scdc_print_flag(m, "Scrambling Enabled", st->scrambling_enabled); scdc_print_flag(m, "Scrambling Detected", st->scrambling_detected); + scdc_print_str(m, "FRL Rate", drm_scdc_frl_rate_str(st->rate)); + scdc_print_dec(m, "FFE Levels", st->ffe_levels); =20 if (st->tmds_bclk_x40) scdc_print_str(m, "TMDS Bit Clock Ratio", "1/40"); @@ -466,10 +581,17 @@ static int scdc_status_show(struct seq_file *m, void = *data) scdc_print_flag(m, "Channel 0 Locked", st->stf.status0.flags.ch0_locked); scdc_print_flag(m, "Channel 1 Locked", st->stf.status0.flags.ch1_locked); scdc_print_flag(m, "Channel 2 Locked", st->stf.status0.flags.ch2_locked); + if (drm_scdc_num_frl_lanes(st->rate) =3D=3D 4) + scdc_print_flag(m, "Lane 3 Locked", st->stf.status0.flags.ln3_locked); + + scdc_print_flag(m, "Sink Ready For Link Training", st->stf.status0.flags.= flt_ready); + scdc_print_flag(m, "Sink Failed To Decode DSC", st->stf.status0.flags.dsc= _fail); =20 scdc_print_dec(m, "Channel 0 Errors", st->error_count[0]); scdc_print_dec(m, "Channel 1 Errors", st->error_count[1]); scdc_print_dec(m, "Channel 2 Errors", st->error_count[2]); + if (drm_scdc_num_frl_lanes(st->rate) =3D=3D 4) + scdc_print_dec(m, "Lane 3 Errors", st->error_count[3]); =20 return 0; =20 diff --git a/include/drm/display/drm_scdc.h b/include/drm/display/drm_scdc.h index 3d58f37e8ed8..56cd909edac9 100644 --- a/include/drm/display/drm_scdc.h +++ b/include/drm/display/drm_scdc.h @@ -29,6 +29,7 @@ #define SCDC_SOURCE_VERSION 0x02 =20 #define SCDC_UPDATE_0 0x10 +#define SCDC_FLT_UPDATE (1 << 5) #define SCDC_READ_REQUEST_TEST (1 << 2) #define SCDC_CED_UPDATE (1 << 1) #define SCDC_STATUS_UPDATE (1 << 0) @@ -46,6 +47,10 @@ #define SCDC_CONFIG_0 0x30 #define SCDC_READ_REQUEST_ENABLE (1 << 0) =20 +#define SCDC_CONFIG_1 0x31 +#define SCDC_FRL_RATE 0x0f +#define SCDC_FFE_LEVELS 0xf0 + #define SCDC_STATUS_FLAGS_0 0x40 #define SCDC_CH2_LOCK (1 << 3) #define SCDC_CH1_LOCK (1 << 2) @@ -54,6 +59,7 @@ #define SCDC_CLOCK_DETECT (1 << 0) =20 #define SCDC_STATUS_FLAGS_1 0x41 +#define SCDC_STATUS_FLAGS_2 0x42 =20 #define SCDC_ERR_DET_0_L 0x50 #define SCDC_ERR_DET_0_H 0x51 @@ -65,6 +71,9 @@ =20 #define SCDC_ERR_DET_CHECKSUM 0x56 =20 +#define SCDC_ERR_DET_3_L 0x57 +#define SCDC_ERR_DET_3_H 0x58 + #define SCDC_TEST_CONFIG_0 0xc0 #define SCDC_TEST_READ_REQUEST (1 << 7) #define SCDC_TEST_READ_REQUEST_DELAY(x) ((x) & 0x7f) diff --git a/include/drm/display/drm_scdc_helper.h b/include/drm/display/dr= m_scdc_helper.h index c066c1158275..a1b73f0be73f 100644 --- a/include/drm/display/drm_scdc_helper.h +++ b/include/drm/display/drm_scdc_helper.h @@ -24,6 +24,7 @@ #ifndef DRM_SCDC_HELPER_H #define DRM_SCDC_HELPER_H =20 +#include #include =20 #include @@ -40,10 +41,10 @@ struct drm_scdc_status_flags { bool ch0_locked : 1; bool ch1_locked : 1; bool ch2_locked : 1; - bool rsvd_4 : 1; + bool ln3_locked : 1; bool rsvd_5 : 1; - bool rsvd_6 : 1; - bool rsvd_7 : 1; + bool flt_ready : 1; + bool dsc_fail : 1; } flags __packed; u8 data; } status0; @@ -51,19 +52,68 @@ struct drm_scdc_status_flags { /* Status Register 1 */ union { struct { - bool rsvd_0 : 1; - bool rsvd_1 : 1; - bool rsvd_2 : 1; - bool rsvd_3 : 1; - bool rsvd_4 : 1; - bool rsvd_5 : 1; - bool rsvd_6 : 1; - bool rsvd_7 : 1; + u8 ln0_training_pattern : 4; + u8 ln1_training_pattern : 4; } flags __packed; u8 data; } status1; + + /* Status Register 2 */ + union { + struct { + u8 ln2_training_pattern : 4; + u8 ln3_training_pattern : 4; + } flags __packed; + u8 data; + } status2; +}; + +enum drm_scdc_frl_rate { + SCDC_FRL_RATE_OFF =3D 0, + SCDC_FRL_RATE_3X3 =3D 1, + SCDC_FRL_RATE_6X3 =3D 2, + SCDC_FRL_RATE_6X4 =3D 3, + SCDC_FRL_RATE_8X4 =3D 4, + SCDC_FRL_RATE_10X4 =3D 5, + SCDC_FRL_RATE_12X4 =3D 6, + SCDC_FRL_RATE_RESV_7 =3D 7, + SCDC_FRL_RATE_RESV_8 =3D 8, + SCDC_FRL_RATE_RESV_9 =3D 9, + SCDC_FRL_RATE_RESV_10 =3D 10, + SCDC_FRL_RATE_RESV_11 =3D 11, + SCDC_FRL_RATE_RESV_12 =3D 12, + SCDC_FRL_RATE_RESV_13 =3D 13, + SCDC_FRL_RATE_RESV_14 =3D 14, + SCDC_FRL_RATE_RESV_15 =3D 15 }; =20 +/** + * drm_scdc_num_frl_lanes - get number of lanes for a given FRL rate + * @rate: one of &enum drm_scdc_frl_rate + * + * For a given @rate, return the number of lanes it uses. + * + * Returns: %-EINVAL if @rate is not a valid FRL rate, or the number of la= nes + * for a given &enum drm_scdc_frl_rate on success (including %0 for "off") + */ +static inline __pure int drm_scdc_num_frl_lanes(enum drm_scdc_frl_rate rat= e) +{ + switch (rate) { + case SCDC_FRL_RATE_OFF: + return 0; + case SCDC_FRL_RATE_3X3: + case SCDC_FRL_RATE_6X3: + return 3; + case SCDC_FRL_RATE_6X4: + case SCDC_FRL_RATE_8X4: + case SCDC_FRL_RATE_10X4: + case SCDC_FRL_RATE_12X4: + return 4; + default: + return -EINVAL; + } +} + struct drm_scdc_state { /** @stf: contents of the status flag registers */ struct drm_scdc_status_flags stf; @@ -76,8 +126,12 @@ struct drm_scdc_state { * clock period, false if it's 1/10th of the clock period. */ bool tmds_bclk_x40; - /** @error_count: character error counts for each channel */ - u16 error_count[3]; + /** @rate: FRL rate set by the source */ + enum drm_scdc_frl_rate rate : 4; + /** @ffe_levels: The FFE levels for @rate set by the source */ + u8 ffe_levels : 4; + /** @error_count: character error counts for each channel/link */ + u16 error_count[4]; }; =20 int drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, @@ -128,9 +182,12 @@ bool drm_scdc_set_high_tmds_clock_ratio(struct drm_con= nector *connector, bool se =20 int drm_scdc_read_status0_flags(struct drm_connector *connector, struct drm_scdc_status_flags *flags); +int drm_scdc_read_status1_2_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags); int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_state *state); -int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[3]); +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 coun= ter[4], + unsigned int num_lanes); void drm_scdc_debugfs_init(struct drm_connector *connector, struct dentry = *root); =20 #endif --=20 2.54.0