Bug 870448

Summary: no backligt on HP g6, needs i915.invert_brightness=1
Product: [Fedora] Fedora Reporter: Mads Kiilerich <mads>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED INSUFFICIENT_DATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 18CC: airlied, ajax, gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda, mads
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Last Closed: 2013-04-01 20:02:18 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
lshw, dmesg, journal, Xorg.0.log none

Description Mads Kiilerich 2012-10-26 14:19:25 UTC 
Created attachment 633881 [details]
lshw, dmesg, journal, Xorg.0.log

On HP Pavilion g6 Notebook PC it looks like a live USB fails to boot. KMS leaves a black display.

Googling hints that something has been reversed. It turns out thatadjusting the backlight level with the relevant keys actually works and reveals fine graphics.

Booting with i915.invert_brightness=1 solves the problem ... but will probably break other machines.

(The direction of up/down was also reversed ... but I don't remember if it was with or without invert_brightness. That is however less of a problem.)

I guess this model needs some kind of quirk.

It has been discussed elsewhere but apperently never upstreamed:
http://unix.stackexchange.com/questions/30580/black-screen-at-boot-with-mint-and-ubuntu-live-cds
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/765438

kernel-3.6.2-2.fc18.x86_64

Bugzilla hints that bug 812544 might be related. That is possible - it doesn't provide enough information to know for sure.
Comment 1 Mads Kiilerich 2012-10-30 18:45:13 UTC 
It seems to be related to https://bugs.freedesktop.org/show_bug.cgi?id=48435 .

One solution seems to be to add a quirk as it is done for Acer Aspire 5734Z in 
http://www.serverphorums.com/read.php?12,462858,462861#msg-462861

Another (better?) solution seems to be to fix the root cause and remove i915.invert_brightness as proposed in the http://web.archiveorange.com/archive/v/rNRcWpAp3NoK7TDlUdOG thread.

3.7.0-0.rc3.git0.1.fc19.i686.PAEdebug do however still have i915.invert_brightness so the patch must have been forgotten or rejected somewhere / somehow.
Comment 2 Josh Boyer 2012-11-13 15:01:32 UTC 
Dave, Adam, any preference on which fix to pursue here?
Comment 3 Josh Boyer 2013-04-01 19:43:31 UTC 
Are you still seeing this with 3.8.x?
Comment 4 Mads Kiilerich 2013-04-01 19:58:25 UTC 
I no longer have access to that machine and cannot verify.
Comment 5 Josh Boyer 2013-04-01 20:02:18 UTC 
OK, thank you for letting us know and sorry for the delay in response.

We'll close this out for now.  If you or someone else happens to come across a machine like that, please reopen.