linux-kernel - Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

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Message-ID: <87bmzr2941.fsf@intel.com>
Date:   Tue, 13 Sep 2016 16:59:58 +0300
From:   Jani Nikula <jani.nikula@...ux.intel.com>
To:     James Hogan <james@...anarts.com>,
        James Bottomley <James.Bottomley@...senpartnership.com>
Cc:     "Syrjala\, Ville" <ville.syrjala@...el.com>,
        intel-gfx <intel-gfx@...ts.freedesktop.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>
Subject: Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Sun, 11 Sep 2016, James Hogan <james@...anarts.com> wrote:
> I've just bisected a similar (same?) problem (slow increase and
> decrease of screen brightness with a period of a few seconds) to the
> same commit (this is on a Dell XPS 13 laptop)
>
> commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> Author: Ville Syrjälä <ville.syrjala@...ux.intel.com>
> Date:   Mon Apr 11 10:23:51 2016 +0300
>
>     drm/i915: Get panel_type from OpRegion panel details
>
> the difference for me is that good commits used the acpi backlight,
> and bad ones used the intel backlight (/sys/class/backlight/). Its
> like intel_backlight is fighting with the firmware to control the
> backlight or something. Reverting the commit on v4.7.3 switches it
> back to the acpi backlight and all works nicely again.
>
> let me know if I can provide anything else to help debug.

Please try [1].

BR,
Jani.

[1] http://patchwork.freedesktop.org/patch/msgid/1473758539-21565-1-git-send-email-ville.syrjala@linux.intel.com


-- 
Jani Nikula, Intel Open Source Technology Center