On Tue, May 22, 2012 at 6:15 PM, Zdenek Kabelac <zdenek.kabelac at gmail.com> wrote: > 2012/5/22 Zdenek Kabelac <zdenek.kabelac at gmail.com>: >> 2012/5/22 Daniel Vetter <daniel at ffwll.ch>: >>> On Tue, May 22, 2012 at 04:36:30PM +0200, Zdenek Kabelac wrote: >>>> 2012/5/22 Daniel Vetter <daniel at ffwll.ch>: >>>> > On Tue, May 22, 2012 at 02:08:46PM +0200, Zdenek Kabelac wrote: >>>> >> Hi >>>> >> >>>> >> I've updated to 3.4 kernel, and now I'm noticing slight changes in >>>> >> brightness on colorful images. >>>> >> It seems the change is mostly visibly on ?'darker' images i.e. it's >>>> >> not really visible on white background. >>>> >> >>>> >> When I reboot back to 3.3 ?kernel - brightness changes are gone - so I >>>> >> do not suspect hw fault of my T61 display. >>>> >> I guess once in past there has been already such bug, so this problem >>>> >> seems to me like reintroducing the same >>>> >> problem again. >>>> >> >>>> >> xorg-x11-server-Xorg-1.12.1-1.fc18.x86_64 >>>> >> with SNA intel driver build from git repo. >>>> >> T61, 965GM >>>> >> >>>> >> Is this a know issue ? >>>> >> Is bisect needed ? >>>> > >>>> > You're the first one to report things, so a bisect would be highly >>>> > appreciated. Also I'm a bit confused about what you mean by 'changing >>>> > brightness'. Can you please try to explain this a bit more? >>>> > >>>> >>>> I've some default gnome picture like this one: >>>> https://lh6.googleusercontent.com/-96ZhFbfLX_M/ThHsm0ZxBgI/AAAAAAAAFQQ/3ApjzYgulso/s400/gnome-3-login-screen.png >>>> >>>> When I watch the picture for some period of time ?I'm noticing slight >>>> changes in the picture brightness looking like small change in LUT >>>> table or something like that. >>>> If the picture is white I'm not noticing any change. >>>> (Initially I've thought my display dies - but reboot to 3.3 fixed the >>>> issue immediately). >>> >>> "for some period", does that mean it takes you a while to notice the >>> changes (because they're tiny), or are the changes happend just rather slowly? >>> >> >> Deviation in picture is not huge - but gets noticeable by my eyes and >> it's annoying, >> it's like several seconds between each minor change. >> >> If I've monotone background in i.e. text editor ?the change is >> practically not visibible, >> but if watch some digicam photos full screen they are quite obvious. >> >> Not sure if that has any influence (not tested without) ?I'm using >> some icc profile >> ('xcalib') to get away from blue of IBM display. >> >>>> Is there any suspecting patch for this chipset I should try to revert ? >>> >>> Tbh I have no idea. If there's no changes when the picture is white, it >>> can't be the backlight, we haven't frobbed around with the gamma stuff and >>> temporal dithering is disabled, too. If you can bisect this it would >>> greatly help. >> >> ok, I'll play this game in the evening if there is nothing obvious. >> > > And we have a winner - cec2f356d59d9e070413e5966a3c5a1af136d948 > Hmm, seems like your display doesn't like to be downclocked, or rather you don't like it to be downclocked :) The reason this patch triggered it is because it does a better job of finding a compatible clock. You can disable lvds downclocking on the kernel command line by setting i915.lvds_downclock=0 Sean > drm/i915: Only look for matching clocks for LVDS downclock > > reverting just ?this patch for vanilla 3.4 ?fixes the problem for my T61. > (I've not tried to play with those individial 3 pieces inside this patch > to check exactly which one is responsible) > > Zdenek > > Here is the bisect game: > git bisect start > # bad: [acc73fb11695b564dc485b1f98f8237bbdc0742f] Remove ioctl warning > git bisect bad acc73fb11695b564dc485b1f98f8237bbdc0742f > # good: [c16fa4f2ad19908a47c63d8fa436a1178438c7e7] Linux 3.3 > git bisect good c16fa4f2ad19908a47c63d8fa436a1178438c7e7 > # bad: [141124c02059eee9dbc5c86ea797b1ca888e77f7] Delete all instances > of asm/system.h > git bisect bad 141124c02059eee9dbc5c86ea797b1ca888e77f7 > # good: [3b59bf081622b6446db77ad06c93fe23677bc533] Merge > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next > git bisect good 3b59bf081622b6446db77ad06c93fe23677bc533 > # good: [424a6f6ef990b7e9f56f6627bfc6c46b493faeb4] Merge tag > 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 > git bisect good 424a6f6ef990b7e9f56f6627bfc6c46b493faeb4 > # bad: [be53bfdb8088e9d1924199cc1a96e113756b1075] Merge branch > 'drm-next' of git://people.freedesktop.org/~airlied/linux > git bisect bad be53bfdb8088e9d1924199cc1a96e113756b1075 > # good: [828006de1bddf83b6ecf03ec459c15f7c7c22db7] Merge tag > 'asoc-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound > into topic/asoc > git bisect good 828006de1bddf83b6ecf03ec459c15f7c7c22db7 > # skip: [496a73bbecb81e6753715995e4519d152f814667] drm/nv50/pm: use > hwsq for engine reclocking too > git bisect skip 496a73bbecb81e6753715995e4519d152f814667 > # skip: [c11dd0da5277596d0ccdccb745b273d69a94f2d7] drm/nouveau/pm: fix > oops if chipset has no pm support at all > git bisect skip c11dd0da5277596d0ccdccb745b273d69a94f2d7 > # skip: [07cafff288266c3aa082f4bda3d47989e73ee85d] ALSA: hda/conexant > - Clear unsol events on unused pins > git bisect skip 07cafff288266c3aa082f4bda3d47989e73ee85d > # bad: [f3298532f71f163877b9003009d6e1eefe988258] drm/nvc0: add > initial memory type detection > git bisect bad f3298532f71f163877b9003009d6e1eefe988258 > # bad: [019d96cb55ade38a4b4a52bba0304e8cd681f30a] drm: add some caps > for userspace to discover more info for dumb KMS driver (v2) > git bisect bad 019d96cb55ade38a4b4a52bba0304e8cd681f30a > # bad: [5c0480f21f9896c443b0e65d779c8e09a695da7b] drm/i915: fall > through pwrite_gtt_slow to the shmem slow path > git bisect bad 5c0480f21f9896c443b0e65d779c8e09a695da7b > # bad: [8e636784b6f76653d358d521af9c2a8c246df38b] drm/i915: fixup > assert_pipe to take the pipe A quirk into account > git bisect bad 8e636784b6f76653d358d521af9c2a8c246df38b > # bad: [23c99e775d14f01ba45a5affd2fb51af4328359c] drm/i915: Fix > assert_pch_hdmi_disabled to mention HDMI (not DP) > git bisect bad 23c99e775d14f01ba45a5affd2fb51af4328359c > # bad: [a7516a05311d0e2deb8ce8ae8b8c12a513ca8ca2] drm/i915: split out > pll divider code > git bisect bad a7516a05311d0e2deb8ce8ae8b8c12a513ca8ca2 > # bad: [5a117db77e47e3946d1aaa7ce8deafafd9d76746] drm/i915: there is > no pipe CxSR on ironlake > git bisect bad 5a117db77e47e3946d1aaa7ce8deafafd9d76746 > # good: [0b8ecdda1943a05c8e7896f0b5f1addf39269927] drm/i915: Silence _DSM errors > git bisect good 0b8ecdda1943a05c8e7896f0b5f1addf39269927
