On 11/14/2013 02:24 PM, Jani Nikula wrote: > > Hi Mario - > > On Wed, 13 Nov 2013, Mario Kleinsasser <mario.kleinsasser+linux-kernel@xxxxxxxxx> wrote: >> In the last three weeks I've narrowed down the bug described in the >> subject through Ubuntu launchpad. My new Laptop (Acer Aspire V5-573G) >> with new Haswell CPU shows a black screen on reboot because the >> brightness is on zero level. I verified this behaviour with the latest >> mainline kernel from >> http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.12-trusty/ > > Thanks for the report. I'll have to ask you to try some kernels, and > logs running them, etc. that IMHO are better suited attached to a bug > report than cluttered on the mailing list. Please file a bug on > DRM/Intel at [1]. Reference your mail. There it will also pop up in our > bug team's searches, and has a better chance of not falling under the > radar. :) > >> I have done the bisect process and tracked the bug down to the >> following commit. >> >> For explanation: >> good commit means: The laptop starts with display brightness on full >> power, but low(er) resolution and the Fn+ keys are not working >> bad commit means: The laptop starts with black display (0 brightness), >> Fn+ keys are working and you can level up the brightness trough the >> Fn+ keys. The resolution is the native LCD hardware display resolution >> >> Bisect output: >> >> 70b12bb415463c1bd146b67c5fbf6784fd046ad9 is the first bad commit >> commit 70b12bb415463c1bd146b67c5fbf6784fd046ad9 >> Author: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> >> Date: Tue Nov 20 13:32:30 2012 -0200 >> >> drm/i915: promote Haswell to full support >> >> Since it should be working a little bit better now. >> >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> >> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> >> >> :040000 040000 f93a7761de2157a8be61f20ca9a5499264bb5c55 >> 1fed098470278830f06b0bca1706f61ba231d38d M drivers >> >> For the full bug report and the additional hardware information please >> see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1239183 >> >> I've also searched the LKML and maybe this bug could be in conjunction >> with http://marc.info/?t=137837786100005&r=1&w=2 > > You only start using our driver for Haswell from the first "bad" commit, > and then we actually serve the ACPI opregion backlight requests. This > explains the backlight Fn keys in your good/bad commit explanations. If > this is a known bug in ACPI, it also explains the zero backlight. It's actually a bug in firmware and we try to work around it in ACPI video module :-) >From the description it indeed seems to be the firmware initial zero brightness level bug to me. Thanks, Aaron > > There's two branches I'd like you to try: > > 1) linux-next branch of [2]. This should contain a fix for some ACPI > initial backlight issues. (CC Aaron for this.) > > 2) backlight-rework branch of [3]. What the branch name says. > > Please add drm.debug=0xe module parameter and attach full dmesg to the > bug. > > > Thanks, > Jani. > > > [1] https://bugs.freedesktop.org/enter_bug.cgi?product=DRI > [2] http://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git > [3] git://gitorious.org/jani/drm.git > > > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
