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From: Stephen Boyd <swboyd@chromium.org>
To: Kuogee Hsieh <quic_khsieh@quicinc.com>,
	agross@kernel.org, airlied@linux.ie, bjorn.andersson@linaro.org,
	daniel@ffwll.ch, dmitry.baryshkov@linaro.org,
	robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org
Cc: quic_abhinavk@quicinc.com, quic_aravindh@quicinc.com,
	quic_sbillaka@quicinc.com, freedreno@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] drm/msm/dp: remove fail safe mode related code
Date: Mon, 25 Apr 2022 23:00:57 -0700	[thread overview]
Message-ID: <CAE-0n53kv+NPJ-4Cpjy_FeJT5xOo7fLNz24fyGUcjy6ucccjbQ@mail.gmail.com> (raw)
In-Reply-To: <1650952595-27783-1-git-send-email-quic_khsieh@quicinc.com>

Quoting Kuogee Hsieh (2022-04-25 22:56:35)
> Current DP driver implementation has adding safe mode done at
> dp_hpd_plug_handle() which is expected to be executed under event
> thread context.
>
> However there is possible circular locking happen (see blow stack trace)
> after edp driver call dp_hpd_plug_handle() from dp_bridge_enable() which
> is executed under drm_thread context.
>
> After review all possibilities methods and as discussed on
> https://patchwork.freedesktop.org/patch/483155/, supporting EDID
> compliance tests in the driver is quite hacky. As seen with other
> vendor drivers, supporting these will be much easier with IGT. Hence
> removing all the related fail safe code for it so that no possibility
> of circular lock will happen.
[...]
>
> Changes in v2:
> -- re text commit title
> -- remove all fail safe mode
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>

Should add some Fixes tags here, probably for the first introduction of
this logic and the one that moved stuff around to try to avoid the
lockdep warning.

WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <swboyd@chromium.org>
To: Kuogee Hsieh <quic_khsieh@quicinc.com>,
	agross@kernel.org, airlied@linux.ie, bjorn.andersson@linaro.org,
	daniel@ffwll.ch, dmitry.baryshkov@linaro.org,
	 robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org
Cc: quic_sbillaka@quicinc.com, linux-arm-msm@vger.kernel.org,
	quic_abhinavk@quicinc.com, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, quic_aravindh@quicinc.com,
	freedreno@lists.freedesktop.org
Subject: Re: [PATCH v2] drm/msm/dp: remove fail safe mode related code
Date: Mon, 25 Apr 2022 23:00:57 -0700	[thread overview]
Message-ID: <CAE-0n53kv+NPJ-4Cpjy_FeJT5xOo7fLNz24fyGUcjy6ucccjbQ@mail.gmail.com> (raw)
In-Reply-To: <1650952595-27783-1-git-send-email-quic_khsieh@quicinc.com>

Quoting Kuogee Hsieh (2022-04-25 22:56:35)
> Current DP driver implementation has adding safe mode done at
> dp_hpd_plug_handle() which is expected to be executed under event
> thread context.
>
> However there is possible circular locking happen (see blow stack trace)
> after edp driver call dp_hpd_plug_handle() from dp_bridge_enable() which
> is executed under drm_thread context.
>
> After review all possibilities methods and as discussed on
> https://patchwork.freedesktop.org/patch/483155/, supporting EDID
> compliance tests in the driver is quite hacky. As seen with other
> vendor drivers, supporting these will be much easier with IGT. Hence
> removing all the related fail safe code for it so that no possibility
> of circular lock will happen.
[...]
>
> Changes in v2:
> -- re text commit title
> -- remove all fail safe mode
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>

Should add some Fixes tags here, probably for the first introduction of
this logic and the one that moved stuff around to try to avoid the
lockdep warning.

  reply	other threads:[~2022-04-26  6:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-26  5:56 [PATCH v2] drm/msm/dp: remove fail safe mode related code Kuogee Hsieh
2022-04-26  5:56 ` Kuogee Hsieh
2022-04-26  6:00 ` Stephen Boyd [this message]
2022-04-26  6:00   ` Stephen Boyd
2022-04-26 17:36   ` Abhinav Kumar
2022-04-26 17:36     ` Abhinav Kumar
2022-04-26 18:48 ` Doug Anderson
2022-04-26 18:48   ` Doug Anderson

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