[Intel-gfx] Screen goes blank @30 seconds into boot

Jonathan Nieder jrnieder at gmail.com
Wed Feb 22 12:03:08 CET 2012

(resending after subscription to appease list spam filter.
 Keith and Joel, sorry for the duplicate message)
Hi intel-gfx list,

Keith Packard wrote:
> On Thu, 26 Jan 2012 06:54:48 -0500, Joel Heaton <jheaton5 at comcast.net> wrote:

>> System: Dell Inspiron One
>> Chipset: intel H61 Express
>> CPU: Intel Pentium Dual Core Intel Core i3/i5i7 (this machine is
>> probably an i3
>> Video: Intel HD/HD 2000/HD 3000
>> When booting the screen goes blank about 80% through the boot cycle.
>> The system is still running, I can log in blind and execute reboot
>> command.
> Is the monitor backlight on or off? If off, can you try finding a bright
> light and shining it on the monitor to see if the image is present, but
> the backlight simply disabled?

Interesting question.  Joel?

>> I ssh into the system from another computer.
>> kern.log reports "Firmware Bug: ACPI: No _BQC method, cannot determine
>> initial brightness"
> The last bug we saw with this was a system that did leave the monitor
> off. Here's a patch that fixed that machine:
> Keith Packard <keithp at keithp.com> (December 31) (lkml me patch sent)
> Subject: [PATCH] acpi/video: Don't restore backlight to 0 at boot time

No change, alas, when Joel tried this patch[1]:

| I made the change by editing drivers/acpi/video.c but the bug is
| recreated.

Cherry-picking commit 7885d2052bd ("drm/i915: mask transcoder select
bits before setting them on LVDS") did not help either.  More details
including some kernel logs and an acpidump at [1].

Thanks and hope that helps,

[1] http://bugs.debian.org/660394

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