Re: [BISECTED] drm: random hang since 620f378 "drm: prune modes when..."

From: Mathieu Taillefumier
Date: Wed Dec 16 2009 - 07:19:43 EST

You can disable most of that code by loading i915 with 'powersave=0'.
If that patch really is at fault the powersave=0 should work around the
issue as well.

It's been implicated in another issue (some display flicker and
underruns) so I'm pretty sure there's something wrong with it in some
configurations at least...
Could it be also that the powersave feature produces gpu hangs when xserver is run the first time (after a cold boot). I have serious issues the intel drm starting at v2.6.32-rc2 (I can not use the v2.6.32 series on my laptop) while the same xorg stack works well with the v2.6.31 series. I try to bisect this problem and obtained this (sorry it is a bit long):

git bisect start 'drivers/gpu' 'arch/x86_64/'
# bad: [053fe57ac249a9531c396175778160d9e9509399] Merge git://
git bisect bad 053fe57ac249a9531c396175778160d9e9509399
# good: [74fca6a42863ffacaf7ba6f1936a9f228950f657] Linux 2.6.31
git bisect good 74fca6a42863ffacaf7ba6f1936a9f228950f657
# bad: [d8a2d0e00c0d5a0d55e14b884bff034205015e51] drm/i915: HDMI hardware workar
ound for Ironlake
git bisect bad d8a2d0e00c0d5a0d55e14b884bff034205015e51
# bad: [d50ba256b5f1478e15accfcfda9b72fd7a661364] drm/kms: start adding command
line interface using fb.
git bisect bad d50ba256b5f1478e15accfcfda9b72fd7a661364
# good: [551ebd837c75fc75df81811a18b7136c39cab487] drm/radeon/kms: add rn50/r100
/r200 CS tracker.
git bisect good 551ebd837c75fc75df81811a18b7136c39cab487
# good: [fdd5cace733370ab7a518a98ef084e02aa76fdea] drm/radeon/kms: Don't kzalloc
memory which is immediately overwritten.
git bisect good fdd5cace733370ab7a518a98ef084e02aa76fdea
# good: [698443d9ec1a33eff65b27b9514e06998bf57eb3] drm/radeon/kms: disable VGA r
endering engine before taking over VRAM
git bisect good 698443d9ec1a33eff65b27b9514e06998bf57eb3
# good: [c214271563c00f2721c5111e27b53bf06dabc6e4] drm/radeon: consolidate famil
y flags used in pciids.
git bisect good c214271563c00f2721c5111e27b53bf06dabc6e4
# good: [93dc6c2b0d97a55508144073838e041140b206cd] drm/edid: Detailed standard t
iming blocks have six timings, not five.
git bisect good 93dc6c2b0d97a55508144073838e041140b206cd
# good: [4bbd4973703bf8a5f00f05eff30a99cd9814f37f] drm/radeon/kms: enable r600 t
v outputs.
git bisect good 4bbd4973703bf8a5f00f05eff30a99cd9814f37f
# good: [513bcb4655e68706594e45dfa1d4b181500110ba] drm/radeon/kms: don't require
up to 64k allocations. (v2)
git bisect good 513bcb4655e68706594e45dfa1d4b181500110ba


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