linux-kernel - Re: [4.4-rc1][Regression] drm/i915: Check live status before reading edid

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Message-ID: <87lh63uago.fsf@intel.com>
Date:	Mon, 29 Feb 2016 11:33:59 +0200
From:	Jani Nikula <jani.nikula@...ux.intel.com>
To:	Joseph Salisbury <joseph.salisbury@...onical.com>,
	sonika.jindal@...el.com
Cc:	shashank.sharma@...el.com, rodrigo.vivi@...el.com,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	David Airlie <airlied@...ux.ie>,
	intel-gfx <intel-gfx@...ts.freedesktop.org>,
	dri-devel <dri-devel@...ts.freedesktop.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [4.4-rc1][Regression] drm/i915: Check live status before reading edid

On Wed, 24 Feb 2016, Joseph Salisbury <joseph.salisbury@...onical.com> wrote:
> Hi Sonika,
>
> A kernel bug report was opened against Ubuntu [0].  After a kernel
> bisect, it was found that reverting the following commit resolved this bug:
>
> commit 237ed86c693d8a8e4db476976aeb30df4deac74b
> Author: Sonika Jindal <sonika.jindal@...el.com>
> Date:   Tue Sep 15 09:44:20 2015 +0530
>
>     drm/i915: Check live status before reading edid
>
>
>
> The regression was introduced as of v4.4-rc1.
>
> I was hoping to get your feedback, since you are the patch author.  Do
> think increasing the number of tries in intel_hdmi_detect() is worth
> trying?  Do you think gathering any additional data will help diagnose
> this issue, or would it be best to submit a revert request?

There are at least the following commits claiming to fix issues in the
above commit. Please make sure you have them.

BR,
Jani.


commit 8d409cb3e8a24196be7271defafd4638f3e0b514
Author: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Date:   Wed Feb 10 19:59:05 2016 +0200

    drm/i915: Fix hpd live status bits for g4x

commit 3d8acd1f667b45c531401c8f0c2033072e32a05d
Author: Gary Wang <gary.c.wang@...el.com>
Date:   Wed Dec 23 16:11:35 2015 +0800

    drm/i915: increase the tries for HDMI hotplug live status checking

commit 97f9010af05c15e0b7e6b4ef6ff8cb0ebb7e7715
Author: Daniel Vetter <daniel.vetter@...ll.ch>
Date:   Fri Dec 11 19:44:15 2015 +0100

    drm/i915: mdelay(10) considered harmful

commit 0f5a9be15797f78c9a34e432f26c796165b6e49a
Author: Imre Deak <imre.deak@...el.com>
Date:   Fri Nov 27 18:55:29 2015 +0200

    drm/i915: take a power domain reference while checking the HDMI live status




-- 
Jani Nikula, Intel Open Source Technology Center