On Thu, Nov 14, 2013 at 8:29 AM, Aaron Lu <aaron.lu@xxxxxxxxx> wrote: > 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 Bug filed as https://bugs.freedesktop.org/show_bug.cgi?id=71596 I will try the given branches and post my results in the filed bug. Thanks for information! Mario > >> >> 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
