From nobody Tue Apr 7 23:40:09 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 192C63CD8D0 for ; Wed, 11 Mar 2026 11:31:47 +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=1773228710; cv=pass; b=nsPofPuzrArAuvk9hKrXR3Ta1NSYmX+1ctx2YR3FY7zT7EZnrOdQgCjz5WUmTtdeqRbu1KuzmUneLGfEeB/AGu455vOU/IMLPfJu+CdCiI2wXTwq7RhEGyVc5Zawfzyu8CTFSjeML+2DNzJdBHrPB+jSAKNDZDxzmSLLmX4MY7g= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773228710; c=relaxed/simple; bh=fem0c399yPiy3PR9aPoK1tNZjoC274H9w+WqlU6XPtM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qWzXNryYr1IXjLXNYdECypV6BVSM+aUMSS2/nC78PqHtczW4vgbGT2klFwffsu4IPCe+qz3oOqDGKzMRODBsRSxyF7Sikjd8HiTW9X4hJhuoPLwp4/owX5utPFjiZUFjkBWNrmTkvZJrdkC70lOvSSuqC2dv2BMst/a7aFwMO0I= 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=PfhfLzrx; 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="PfhfLzrx" ARC-Seal: i=1; a=rsa-sha256; t=1773228686; cv=none; d=zohomail.com; s=zohoarc; b=IxX+zo7Gd/oEBjkZWXW8I2L0Lz4/Xv7FXziEqu1i2F3ibs4ekonxVSop1JsLi6hKSyYHS1u6tz0r+Ox3SH6cB40wgeHHwKslNR/zAVtwcA7nPVxiQD+WEjjoWCcso4gSK5qegByGlEh1qs2C+LtLWL1LN+tMVv8r/aTiI9yG5Kk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1773228686; 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=7Dkscc34h1bPFUV7RCNNNdjClm/eZjD9p2zUaLjFCsU=; b=e3JW38PgMY/lyqEnhSRK0QEC2Q9v4rdkEqvqqZQlJB1pWNsJx6d2QrgU2/hYnbr7/My5SAeMTnMoz1CQnRSbOTne8ts4ScwYqTo2FWoFCzZUM9ZM8IPddljZUrKEQQtoAbG//xRo4wDe1cjAuYRLimne0ic3flhbmT7CpDqbyyo= 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=1773228686; 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=7Dkscc34h1bPFUV7RCNNNdjClm/eZjD9p2zUaLjFCsU=; b=PfhfLzrx+4yik1wxTU4BL557hrOzf+6k/zslDWn3jOVeKbx/HSjZtL8XY36CdUzo +qb4oGRHeZ2i+m/Uo5l3jgJBGlj+ynWrX+9hC56a6E7tTBVvSPtxEpEOrKo7BQGhn5N Jb3DlUrVZqCt5Q2CMjYJTYPc6SPgr9+FZyXZwPG8= Received: by mx.zohomail.com with SMTPS id 1773228684467924.0850833915475; Wed, 11 Mar 2026 04:31:24 -0700 (PDT) From: Nicolas Frattaroli Date: Wed, 11 Mar 2026 12:30:56 +0100 Subject: [PATCH v4 2/2] drm/amd/display: Add support for 'link bpc' property 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: <20260311-link-bpc-v4-2-51775e964720@collabora.com> References: <20260311-link-bpc-v4-0-51775e964720@collabora.com> In-Reply-To: <20260311-link-bpc-v4-0-51775e964720@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , =?utf-8?q?Christian_K=C3=B6nig?= , =?utf-8?q?Ville_Syrj=C3=A4l=C3=A4?= , Daniel Stone , Dmitry Baryshkov Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.14.3 The 'link bpc' DRM property exposes the connector's current display link bits per component value. This allows userspace to discover whether a link has degraded from a higher bit depth to a lower one. Add support for it in amdgpu. Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gp= u/drm/amd/display/amdgpu_dm/amdgpu_dm.c index dfe95c9b8746..cca4dd93bb6d 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -7184,6 +7184,14 @@ static void apply_dsc_policy_for_stream(struct amdgp= u_dm_connector *aconnector, } #endif =20 +static void amdgpu_dm_update_link_bpc(struct drm_connector_state *conn_sta= te, + enum dc_color_depth depth) +{ + /* 6 bpc is an experimental internal format only, use 8 as minimum */ + conn_state->link_bpc =3D clamp(convert_dc_color_depth_into_bpc(depth), 8, + conn_state->max_bpc); +} + static struct dc_stream_state * create_stream_for_sink(struct drm_connector *connector, const struct drm_display_mode *drm_mode, @@ -8981,8 +8989,10 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_d= isplay_manager *dm, adev->mode_info.underscan_vborder_property, 0); =20 - if (!aconnector->mst_root) + if (!aconnector->mst_root) { drm_connector_attach_max_bpc_property(&aconnector->base, 8, 16); + drm_connector_attach_link_bpc_property(&aconnector->base, 16); + } =20 aconnector->base.state->max_bpc =3D 16; aconnector->base.state->max_requested_bpc =3D aconnector->base.state->max= _bpc; @@ -11425,6 +11435,9 @@ static int dm_update_crtc_state(struct amdgpu_displ= ay_manager *dm, goto fail; } =20 + amdgpu_dm_update_link_bpc(drm_new_conn_state, + new_stream->timing.display_color_depth); + /* * TODO: Check VSDB bits to decide whether this should * be enabled or not. --=20 2.53.0