linux-kernel - Re: [PATCH v3] drm/msm/dpu1: don't choke on disabling the writeback connector

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Message-ID: <Z1a3jOB8CutzRZud@hovoldconsulting.com>
Date: Mon, 9 Dec 2024 10:25:32 +0100
From: Johan Hovold <johan@...nel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Rob Clark <robdclark@...il.com>,
	Abhinav Kumar <quic_abhinavk@...cinc.com>,
	Sean Paul <sean@...rly.run>,
	Marijn Suijten <marijn.suijten@...ainline.org>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Simona Vetter <simona.vetter@...ll.ch>,
	linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org, Leonard Lausen <leonard@...sen.nl>,
	György Kurucz <me@...uczgy.com>,
	Johan Hovold <johan+linaro@...nel.org>
Subject: Re: [PATCH v3] drm/msm/dpu1: don't choke on disabling the writeback
 connector

Dmitry,

Looks like you just silently ignored my reviewed feedback, yet included
my conditional reviewed-by tag. Repeating below.

On Sun, Dec 08, 2024 at 07:29:11PM +0200, Dmitry Baryshkov wrote:
> During suspend/resume process all connectors are explicitly disabled and
> then reenabled. However resume fails because of the connector_status check:
> 
> [ 1185.831970] [dpu error]connector not connected 3

Please also include the follow-on resume error. I'm seeing:

	[dpu error]connector not connected 3
	[drm:drm_mode_config_helper_resume [drm_kms_helper]] *ERROR* Failed to resume (-22)

and say something about that this can prevent *displays* from being
enabled on resume in *some* setups (preferably with an explanation why
if you have one).

> It doesn't make sense to check for the Writeback connected status (and
> other drivers don't perform such check), so drop the check.
> 
> Fixes: 71174f362d67 ("drm/msm/dpu: move writeback's atomic_check to dpu_writeback.c")

I noticed that the implementation had this status check also before
71174f362d67 ("drm/msm/dpu: move writeback's atomic_check to
dpu_writeback.c").

Why did this not cause any trouble back then? Or is this not the right
Fixes tag?

> Cc: stable@...r.kernel.org
> Reported-by: Leonard Lausen <leonard@...sen.nl>
> Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/57

Please include mine an György's reports here too.

Since this has dragged on for many months now, more people have run into
this issue and have reported this to you. Giving them credit for this is
the least you can do especially since you failed to include the
corresponding details about how this manifests itself to users in the
commit message:

Reported-by: György Kurucz <me@...uczgy.com>
Link: https://lore.kernel.org/all/b70a4d1d-f98f-4169-942c-cb9006a42b40@kuruczgy.com/

Reported-by: Johan Hovold <johan+linaro@...nel.org>
Link: https://lore.kernel.org/all/ZzyYI8KkWK36FfXf@hovoldconsulting.com/

> Tested-by: Leonard Lausen <leonard@...sen.nl> # on sc7180 lazor
> Tested-by: György Kurucz <me@...uczgy.com>
> Reviewed-by: Johan Hovold <johan+linaro@...nel.org>
> Tested-by: Johan Hovold <johan+linaro@...nel.org>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
> Leonard Lausen reported an issue with suspend/resume of the sc7180
> devices. Fix the WB atomic check, which caused the issue.
> ---
> Changes in v3:
> - Rebased on top of msm-fixes
> - Link to v2: https://lore.kernel.org/r/20240802-dpu-fix-wb-v2-0-7eac9eb8e895@linaro.org

Johan