From nobody Mon Dec 15 01:49:03 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 27B9F30749E for ; Wed, 25 Jun 2025 22:46:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750891569; cv=none; b=s6s2hpbfmgrXh+xuujVZzFFdkIJh4BlZmo++W31rJOoBrsikMYAjtFT71AiGCPbYKTVfnCxGsbMj20uHZHAdBXT5yxGLhPnij5Xw+fHaEGdKmctlHZTlPkJ3rIOOmljPLo9xjWfL7TWuFx7XLxPhXEeYJfTI8n7ExlxPl3pCWEg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750891569; c=relaxed/simple; bh=KpQBq8cTWgHBNZDDJpzS8CHdL8OOqHXQA7o9ZDYM6RI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=ofnZv25AgArCtZuyI7AzhGMc9GJJXUayc0TPnxOd8xbSiy+xaqVJH4SVcIQ3vkQAQILU0tTmlduoi/55dkPrHVGLa4MFIGMV/+1QmMglmY/w1KAux4g92M3lbWJh28vRLrEF6aAQOCMDIS2ACEf/zRRYMi0kD0iA7woZZV3tQWg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=CIUALG0h; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CIUALG0h" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750891564; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=cOrJ0BWmzHP1S8qZkg+9YGmlzCtKwaBoQZ0rsm3ib5U=; b=CIUALG0hAl9bERDSEq0ozcYyVoRmAoCrVHF6/GRlwKkSqGXRGcga+SqzQFOmjet8k5v29n 6BUb4hwJYTQ3kc0d6y+VhEMe4+qQUjJ7pJWe8iX0taWG+tBr2e1Y0JlXv4BWH7NFlRWKcm Jk2CWxxd1vHYeRHbZU+LXsJN+3Suqn8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-308-_XCgAn6hO-qAjMP2R-ffBA-1; Wed, 25 Jun 2025 18:46:02 -0400 X-MC-Unique: _XCgAn6hO-qAjMP2R-ffBA-1 X-Mimecast-MFC-AGG-ID: _XCgAn6hO-qAjMP2R-ffBA_1750891560 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D0D641800268; Wed, 25 Jun 2025 22:45:59 +0000 (UTC) Received: from asrivats-na.rmtustx.csb (unknown [10.2.16.179]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 678C819560A3; Wed, 25 Jun 2025 22:45:56 +0000 (UTC) From: Anusha Srivatsa Date: Wed, 25 Jun 2025 17:44:44 -0500 Subject: [PATCH v2] panel/simple-simple: Identify simple DPI panels using .compatible field 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: <20250625-b4-simple-panel-regression-v2-1-9422d46917ac@redhat.com> X-B4-Tracking: v=1; b=H4sIANt7XGgC/42NSw6CUAxFt0I6toZXQdCR+zAMChRowi99hGgIe /fBChyek9xzN/BiKh6e0QYmq3qdxgB0iaDqeGwFtQ4MFFMa3ynBMkGvw9wLzjxKjyatiT9mmLP cSqacGiEIgdmk0c8ZfxeBO/XLZN/za3WH/Su7OnTIKdfNgzirXPYyqTtertU0QLHv+w+DY4nrx QAAAA== X-Change-ID: 20250624-b4-simple-panel-regression-8ae3ba282fe2 To: Neil Armstrong , Jessica Zhang , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Luca Ceresoli Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Francesco Dolcini , Anusha Srivatsa X-Developer-Signature: v=1; a=ed25519-sha256; t=1750891486; l=8509; i=asrivats@redhat.com; s=20250122; h=from:subject:message-id; bh=KpQBq8cTWgHBNZDDJpzS8CHdL8OOqHXQA7o9ZDYM6RI=; b=Sb9YHTyGFNODaxRqP+TJOHaOR6GP9g6wYOLczCx6IdQblOZgshlmv7RxFrrPsCaLkNa2hu5jJ Ej11NK7/wPwDpH86OsX/KG8pDTE0WdYm/NXh/ow7Dt4DaujUDScVYVE X-Developer-Key: i=asrivats@redhat.com; a=ed25519; pk=brnIHkBsUZEhyW6Zyn0U92AeIZ1psws/q8VFbIkf1AU= X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 The panel allocation in panel_simple_probe() breaks due to not having the panel desc for DPI panels. DPI panels gets probed much later. Currently driver is checking for desc =3D=3D &panel_dpi to do the DPI specific panel desc allocations. This looks hacky. This patch does the following: - Rename panel_dpi_probe() to panel_dpi_get_desc() and call it before panel allocation. panel_dpi_get_desc() returns a panel desc unlike panel_dpi_probe() which returned an int. This way driver has a known connector type while allocating the panel. - panel_dpi_get_desc() returns a panel desc - Add a simple helper is_panel_dpi() to identify a simple DPI panel from a simple panel based on .compatible field Fixes: de04bb0089a9 ("drm/panel/panel-simple: Use the new allocation in pla= ce of devm_kzalloc()") Suggested-by: Luca Ceresoli Suggested-by: Maxime Ripard Cc: Francesco Dolcini Cc: Luca Ceresoli Cc: Maxime Ripard Reported-by: Francesco Dolcini Closes: https://lore.kernel.org/all/20250612081834.GA248237@francesco-nb/ Signed-off-by: Anusha Srivatsa --- Seeing the below trace due to the changes introduced by: Commit de04bb0089a9 ("drm/panel/panel-simple: Use the new allocation in pla= ce of devm_kzalloc()") [ 12.089274] ------------[ cut here ]------------ [ 12.089303] WARNING: CPU: 0 PID: 96 at drivers/gpu/drm/bridge/panel.c:37= 7 devm_drm_of_get_bridge+0xac/0xb8 [ 12.130808] Modules linked in: v4l2_jpeg pwm_imx27(+) imx_vdoa gpu_sched= panel_simple imx6_media(C) imx_media_common (C) videobuf2_dma_contig pwm_bl gpio_keys v4l2_mem2mem fuse ipv6 autofs4 [ 12.147774] CPU: 0 UID: 0 PID: 96 Comm: kworker/u8:3 Tainted: G = C 6.16.0-rc1+ #1 PREEMPT [ 12.157446] Tainted: [C]=3DCRAP [ 12.160418] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 12.166953] Workqueue: events_unbound deferred_probe_work_func [ 12.172805] Call trace: [ 12.172815] unwind_backtrace from show_stack+0x10/0x14 [ 12.180598] show_stack from dump_stack_lvl+0x68/0x74 [ 12.185674] dump_stack_lvl from __warn+0x7c/0xe0 [ 12.190407] __warn from warn_slowpath_fmt+0x1b8/0x1c0 [ 12.195567] warn_slowpath_fmt from devm_drm_of_get_bridge+0xac/0xb8 [ 12.201949] devm_drm_of_get_bridge from imx_pd_probe+0x58/0x164 [ 12.207976] imx_pd_probe from platform_probe+0x5c/0xb0 [ 12.213220] platform_probe from really_probe+0xd0/0x3a4 [ 12.218551] really_probe from __driver_probe_device+0x8c/0x1d4 [ 12.224486] __driver_probe_device from driver_probe_device+0x30/0xc0 [ 12.230942] driver_probe_device from __device_attach_driver+0x98/0x10c [ 12.237572] __device_attach_driver from bus_for_each_drv+0x90/0xe4 [ 12.243854] bus_for_each_drv from __device_attach+0xa8/0x1c8 [ 12.249614] __device_attach from bus_probe_device+0x88/0x8c [ 12.255285] bus_probe_device from deferred_probe_work_func+0x8c/0xcc [ 12.261739] deferred_probe_work_func from process_one_work+0x154/0x2dc [ 12.268371] process_one_work from worker_thread+0x250/0x3f0 [ 12.274043] worker_thread from kthread+0x12c/0x24c [ 12.278940] kthread from ret_from_fork+0x14/0x28 [ 12.283660] Exception stack(0xd0be9fb0 to 0xd0be9ff8) [ 12.288720] 9fa0: 00000000 00000000 = 00000000 00000000 [ 12.296906] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 = 00000000 00000000 [ 12.305089] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 12.312050] ---[ end trace 0000000000000000 ]--- --- Changes in v2: - Add the "Reported-by" and "Closes" tags. - change the compatible with panel-dpi instead of previously used panel_dpi (Luca). - remove DPI entry in platform_of_match() the global panel_desc panel_dpi declaration (Luca). - Edit commit message (Maxime) - Avoid returning NULL, instead return ERR_PTR in panel_dpi_get_desc() - Link to v1: https://lore.kernel.org/r/20250624-b4-simple-panel-regression= -v1-1-a5adf92a7c17@redhat.com --- v2: - Add the "Reported-by" and "Closes" tags. - change the compatible with panel-dpi instead of previously used panel_dpi (Luca). - remove DPI entry in platform_of_match() the global panel_desc panel_dpi declaration (Luca). - Edit commit message (Maxime) - Avoid returning NULL, instead return ERR_PTR in panel_dpi_get_desc() --- drivers/gpu/drm/panel/panel-simple.c | 48 ++++++++++++++++++--------------= ---- 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/p= anel-simple.c index 0a3b26bb4d731c54614e24e38018c308acd5367a..aace1c7d17bdb3c2a0ebd36d164= a858877c2c4c2 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -430,10 +431,7 @@ static const struct drm_panel_funcs panel_simple_funcs= =3D { .get_timings =3D panel_simple_get_timings, }; =20 -static struct panel_desc panel_dpi; - -static int panel_dpi_probe(struct device *dev, - struct panel_simple *panel) +static struct panel_desc *panel_dpi_get_desc(struct device *dev) { struct display_timing *timing; const struct device_node *np; @@ -445,17 +443,17 @@ static int panel_dpi_probe(struct device *dev, np =3D dev->of_node; desc =3D devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL); if (!desc) - return -ENOMEM; + return ERR_PTR(-ENOMEM); =20 timing =3D devm_kzalloc(dev, sizeof(*timing), GFP_KERNEL); if (!timing) - return -ENOMEM; + return ERR_PTR(-ENOMEM); =20 ret =3D of_get_display_timing(np, "panel-timing", timing); if (ret < 0) { dev_err(dev, "%pOF: no panel-timing node found for \"panel-dpi\" binding= \n", np); - return ret; + return ERR_PTR(ret); } =20 desc->timings =3D timing; @@ -473,9 +471,7 @@ static int panel_dpi_probe(struct device *dev, /* We do not know the connector for the DT node, so guess it */ desc->connector_type =3D DRM_MODE_CONNECTOR_DPI; =20 - panel->desc =3D desc; - - return 0; + return desc; } =20 #define PANEL_SIMPLE_BOUNDS_CHECK(to_check, bounds, field) \ @@ -570,6 +566,15 @@ static int panel_simple_override_nondefault_lvds_datam= apping(struct device *dev, return 0; } =20 +static bool is_panel_dpi(struct device *dev) +{ + const struct of_device_id *match; + + match =3D of_match_device(dev->driver->of_match_table, dev); + + return strcmp(match->compatible, "panel-dpi"); +} + static int panel_simple_probe(struct device *dev, const struct panel_desc = *desc) { struct panel_simple *panel; @@ -579,6 +584,13 @@ static int panel_simple_probe(struct device *dev, cons= t struct panel_desc *desc) u32 bus_flags; int err; =20 + /* Is this simple panel a DPI panel */ + if (is_panel_dpi(dev)) { + desc =3D panel_dpi_get_desc(dev); + if (IS_ERR(desc)) + return PTR_ERR(desc); + } + panel =3D devm_drm_panel_alloc(dev, struct panel_simple, base, &panel_simple_funcs, desc->connector_type); if (IS_ERR(panel)) @@ -611,16 +623,8 @@ static int panel_simple_probe(struct device *dev, cons= t struct panel_desc *desc) return -EPROBE_DEFER; } =20 - if (desc =3D=3D &panel_dpi) { - /* Handle the generic panel-dpi binding */ - err =3D panel_dpi_probe(dev, panel); - if (err) - goto free_ddc; - desc =3D panel->desc; - } else { - if (!of_get_display_timing(dev->of_node, "panel-timing", &dt)) - panel_simple_parse_panel_timing_node(dev, panel, &dt); - } + if (!of_get_display_timing(dev->of_node, "panel-timing", &dt)) + panel_simple_parse_panel_timing_node(dev, panel, &dt); =20 if (desc->connector_type =3D=3D DRM_MODE_CONNECTOR_LVDS) { /* Optional data-mapping property for overriding bus format */ @@ -5364,10 +5368,6 @@ static const struct of_device_id platform_of_match[]= =3D { }, { .compatible =3D "microchip,ac69t88a", .data =3D &mchp_ac69t88a, - }, { - /* Must be the last entry */ - .compatible =3D "panel-dpi", - .data =3D &panel_dpi, }, { /* sentinel */ } --- base-commit: 10357824151262636fda879845f8b64553541106 change-id: 20250624-b4-simple-panel-regression-8ae3ba282fe2 Best regards, --=20 Anusha Srivatsa