Messages in this thread | | | Date | Fri, 26 Nov 2010 14:34:39 +0100 | From | Zdenek Kabelac <> | Subject | Re: kernel 2.6.37-rc2 breaks i915 graphics |
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Dne 26.11.2010 10:23, Florian Mickler napsal(a): > On Sun, 21 Nov 2010 18:34:23 +0000 > Chris Vine <chris@cvine.freeserve.co.uk> wrote: > >> On Sun, 21 Nov 2010 10:30:43 +0000 >> Chris Wilson <chris@chris-wilson.co.uk> wrote: >> >>> On Sun, 21 Nov 2010 10:23:44 +0000, Chris Vine >>> <chris@cvine.freeserve.co.uk> wrote: >>>> Hi, >>>> >>>> With kernel 2.6.37-rc2, i915 graphics usually fails on boot-up after >>>> modesetting with my Lenovo S12 netbook which uses the Intel 945GME >>>> Express Integrated Graphics Controller. It displays up to the >>>> point at which modesetting takes place and then usually goes blank. >>>> >>>> There may be some kind of race at work here: first, sometimes >>>> (maybe 1 times in 4) graphics comes up correctly on a first cold >>>> boot, but I have never managed to get it to come up on a warm >>>> reboot. Secondly, graphics can be restored when I know (but cannot >>>> see) that boot-up has concluded, simply by suspending the laptop >>>> and then resuming. Resuming the laptop after a suspend always >>>> brings up the graphics correctly. >>> >>> Add drm.debug=0xe to your boot commandline and compare if there is any >>> difference between a successful cold boot, a broken cold boot and a >>> warm boot. Similarly, comparing the output of intel_reg_dumper after >>> each should yield a few clues as to what stage in the boot process we >>> fail. -Chris >> >> First an additional datum point: 2.6.37-rc1 works normally, so the bug >> is something introduced between 2.6.37-rc1 and 2.6.37-rc2 (to that >> extent it may be related to this bug which reports a similar phenomenon: >> http://lkml.org/lkml/2010/11/21/23 ). >> >> Attached is the dmesg output from a successful cold boot with >> 2.6.37-rc2, an unsuccessful cold boot and an unsuccessful warm boot, >> each with drm.debug=0xe. >> > > I trimmed the failure boot logs to the stuff before suspending, in > order to only compare the boot sequence. > > Looks like only in failure case there are "pipe b > underrun" reported... > In success case, no "pipe b underrun" is reported. > > Also in success case connectors are probed much more often: > > $ grep drm:drm_helper_probe_single_connector_modes dmesg-2.6.37-rc2.succeed | wc -l > 76 > $ grep drm:drm_helper_probe_single_connector_modes dmesg-2.6.37-rc2.*.fail | wc -l > 32 > $ grep drm:drm_helper_probe_single_connector_modes dmesg-2.6.37-rc2.cold.fail | wc -l > 16 > > > I could not spot any other differences both failure modes have in common against the success case. > > If Chris (Wilson) doesn't yet know what could be the bug a bisection > between 2.6.37-rc1 and rc2 might be helpful. > > >> I can't provide the output of intel_reg_dumper: I can't compile the >> latest intel-gpu-tools from git (missing declaration/definition of >> I915_EXE_BLT). Probably something in a relevant library is too old. >>
Reminds me - I need to keep drm_kms_helper disabled for reliable resume on T61:
https://bugzilla.kernel.org/show_bug.cgi?id=19052 https://bugzilla.redhat.com/show_bug.cgi?id=617809
Zdenek
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