[Intel-gfx] i915 (GM45) instability (and an oops)

[Andrew Lutomirski]

I've been running 2.6.35 rc's and xf86-drv-intel git master for
awhile, and X has been a bit unstable.  Every now and then, graphics
freeze completely, except that the mouse still works (I think) and
capslock toggles the LED.

If I switch to a different VT and killall -9 Xorg, everything recovers.

If I switch to a different VT and switch directly back to X, X hangs
completely -- mouse can't move and capslock doesn't work.  Alt-SysRq-R
doesn't work either (not sure why).

It just happened again and I tried something a bit different.  I
switched to a console, did 'echo 1 >i915_wedged', and got an oops:

[20815.509691] [drm] Manually setting wedged to 1
[20815.509701] BUG: sleeping function called from invalid context at
arch/x86/mm/fault.c:1072
[20815.509708] in_atomic(): 0, irqs_disabled(): 1, pid: 4543, name: bash
[20815.509716] Pid: 4543, comm: bash Not tainted 2.6.35-rc6+ #40
[20815.509722] Call Trace:
[20815.509738]  [<ffffffff81036eed>] __might_sleep+0xe8/0xed
[20815.509749]  [<ffffffff81446e2d>] do_page_fault+0x1aa/0x2ac
[20815.509759]  [<ffffffff814441ef>] page_fault+0x1f/0x30
[20815.509770]  [<ffffffff8102c1af>] ? __wake_up_common+0x25/0x84
[20815.509778]  [<ffffffff8102fc53>] __wake_up+0x39/0x4d
[20815.509823]  [<ffffffffa0079608>] i915_wedged_write+0xd4/0x10d [i915]
[20815.509834]  [<ffffffff811b6e0f>] ? security_file_permission+0x16/0x18
[20815.509845]  [<ffffffff810f4f3d>] vfs_write+0xae/0x10b
[20815.509852]  [<ffffffff810f505a>] sys_write+0x4a/0x6e
[20815.509863]  [<ffffffff81002b2b>] system_call_fastpath+0x16/0x1b
[20815.509880] Oops: 0000 [#1] SMP
[20815.509947] last sysfs file:
/sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:00/PNP0C09:00/PNP0C0A:00/power_supply/BAT0/voltage_now
[20815.510097] CPU 1
[20815.510128] Modules linked in: fuse tun tp_smapi thinkpad_ec
cpufreq_ondemand xt_multiport ipt_MASQUERADE iptable_nat nf_nat
ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6
kvm_intel kvm uinput arc4 snd_hda_codec_conexant ecb snd_hda_intel
iwlagn snd_hda_codec snd_hwdep iwlcore snd_seq snd_seq_device snd_pcm
mac80211 thinkpad_acpi snd_timer tpm_tis hwmon cfg80211 tpm iTCO_wdt
i2c_i801 tpm_bios snd iTCO_vendor_support snd_page_alloc microcode
soundcore aes_x86_64 aes_generic xts gf128mul dm_crypt i915
drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded:
scsi_wait_scan]
[20815.510257]
[20815.510257] Pid: 4543, comm: bash Not tainted 2.6.35-rc6+ #40 7465CTO/7465CTO
[20815.510257] RIP: 0010:[<ffffffff8102c1af>]  [<ffffffff8102c1af>]
__wake_up_common+0x25/0x84
[20815.510257] RSP: 0018:ffff8800378f1e28  EFLAGS: 00010082
[20815.510257] RAX: ffffffffffffffe8 RBX: ffff880135770350 RCX: 0000000000000000
[20815.510257] RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffff880135770358
[20815.510257] RBP: ffff8800378f1e68 R08: 0000000000000000 R09: 000000000000000a
[20815.510257] R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000003
[20815.510257] R13: 0000000000000001 R14: 00007fd2044d5000 R15: 0000000000000001
[20815.510257] FS:  00007fd2044a5700(0000) GS:ffff880001f00000(0000)
knlGS:0000000000000000
[20815.510257] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[20815.510257] CR2: 0000000000000000 CR3: 00000000b805c000 CR4: 00000000000406e0
[20815.510257] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[20815.510257] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[20815.510257] Process bash (pid: 4543, threadinfo ffff8800378f0000,
task ffff880137705bc0)
[20815.510257] Stack:
[20815.510257]  ffff880135770000 0000000000000001 00007fd2044d5000
ffff880135770350
[20815.510257] <0> 0000000000000286 0000000000000001 00007fd2044d5000
0000000000000001
[20815.510257] <0> ffff8800378f1ea8 ffffffff8102fc53 ffff8800378f1e98
0000000000000000
[20815.510257] Call Trace:
[20815.510257]  [<ffffffff8102fc53>] __wake_up+0x39/0x4d
[20815.510257]  [<ffffffffa0079608>] i915_wedged_write+0xd4/0x10d [i915]
[20815.510257]  [<ffffffff811b6e0f>] ? security_file_permission+0x16/0x18
[20815.510257]  [<ffffffff810f4f3d>] vfs_write+0xae/0x10b
[20815.510257]  [<ffffffff810f505a>] sys_write+0x4a/0x6e
[20815.510257]  [<ffffffff81002b2b>] system_call_fastpath+0x16/0x1b
[20815.510257] Code: 48 01 78 28 c9 c3 55 48 89 e5 41 57 41 56 41 55
41 54 53 48 83 ec 18 0f 1f 44 00 00 48 8b 47 08 41 89 f4 48 83 e8 18
48 83 c7 08 <4c> 8b 68 18 89 d3 41 89 cf 49 83 ed 18 48 89 7d c8 eb 33
44 8b
[20815.510257] RIP  [<ffffffff8102c1af>] __wake_up_common+0x25/0x84
[20815.510257]  RSP <ffff8800378f1e28>
[20815.510257] CR2: 0000000000000000

I then switched back to Xorg and it was completely frozen.  SysRq+R
did nothing, but SysRq+K got me a VT back.  Xorg was unkillable
(sorry, should have gotten a stack trace, but I didn't).  cat
i915_wedged showed that wedged = 1.  I tried echo 1 >i915_wedged again
and the system froze hard -- even SysRq+B did nothing.

This is my trusty bug-exposing GM45 laptop :)  The backtrace is on 2.6.35-rc6+.

--Andy