From: Jani Nikula <jani.nikula@linux.intel.com>
To: James Courtier-Dutton <james.dutton@gmail.com>,
Takashi Iwai <tiwai@suse.de>
Cc: Intel-gfx@lists.freedesktop.org
Subject: Re: Regression: Backlight not coming on after resume.
Date: Fri, 01 Mar 2013 16:47:33 +0200 [thread overview]
Message-ID: <87ip5bw516.fsf@intel.com> (raw)
In-Reply-To: <CAAMvbhF6k7NyZDNmS1Srp4ox-LKb3KqECibyTBbXg8M+DUrmrQ@mail.gmail.com>
Hi James -
On Fri, 01 Mar 2013, James Courtier-Dutton <james.dutton@gmail.com> wrote:
>> James, try to revert that commit. Does it fix?
>>
>> If so, you should check the output of intel_reg_dumper at broken and
>> working states.
>>
> Can someone point me to a datasheet that relates to this bit of code, so i
> can understand what all the registers do.
> I would like to understand the code in order to suggest a better fix.
https://01.org/linuxgraphics/documentation/driver-documentation-prms
Vol 3 is the relevant volume in each generation. I don't think any of
the docs back up the comments in the bad commit saying "BLC_PWM_CPU_CTL
is cleared to zero automatically when BLC_PWM_CPU_CTL2 and
BLC_PWM_PCH_CTL1 are written" though. I guess it could be some bad
ACPI/BIOS interaction too.
I'd still urge you to file the bug, and attach the dmesgs and register
dumps first. And let us know if the revert fixes it.
BR,
Jani.
prev parent reply other threads:[~2013-03-01 14:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-28 14:56 Regression: Backlight not coming on after resume James Courtier-Dutton
2013-02-28 15:33 ` Jani Nikula
2013-02-28 17:20 ` Takashi Iwai
2013-03-01 8:45 ` James Courtier-Dutton
2013-03-01 14:47 ` Jani Nikula [this message]
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