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

From: Jindal, Sonika
Date: Wed Feb 24 2016 - 22:53:52 EST

Hi Joe,

Yes, first thing to try is to increase the tries.
Can you please point me to the bug and provide more details like platform, monitor, cable.
Are you referring to the same issue as Oleksandr reported where a single link dvi/hdmi cable didnât work and dual link worked?


-----Original Message-----
From: Joseph Salisbury [mailto:joseph.salisbury@xxxxxxxxxxxxx]
Sent: Thursday, February 25, 2016 3:09 AM
To: Jindal, Sonika <sonika.jindal@xxxxxxxxx>
Cc: Sharma, Shashank <shashank.sharma@xxxxxxxxx>; Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx>; Daniel Vetter <daniel.vetter@xxxxxxxx>; Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>; David Airlie <airlied@xxxxxxxx>; intel-gfx <intel-gfx@xxxxxxxxxxxxxxxxxxxxx>; dri-devel <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>
Subject: [4.4-rc1][Regression] drm/i915: Check live status before reading edid

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@xxxxxxxxx>
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?