Ozone GBM: i915_gem_end_cpu_access causes crash.

Ozone GBM: i915_gem_end_cpu_access causes crash.

Only Intel Atom architecture needs the synchronization logic, and we didn't enable GBMs on any Atom devices.
So we can comment it out until it's fixed.

BUG=611968, 612078

[dshwang, 2016-04-22 09:22:32]

Description was changed from

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=605774
==========

to

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=605774
==========

[dshwang, 2016-04-22 09:22:33]

dongseong.hwang@intel.com changed reviewers:
+ hshi@chromium.org, kalin@chromium.org, rookrishna@chromium.org,
spang@chromium.org, tiago.vignatti@intel.com

[dshwang, 2016-04-22 09:22:48]

spang, tiago, could you review?

[dshwang, 2016-04-22 09:53:34]

after more debugging, the crash might not be related to dma_buf sync.

However, dma_buf sync still have some bugs, as it causes the error log [1].
Do you think we need to comment it out until it's fixed?

[1]
2016-04-21T15:44:22.319052-07:00 WARNING kernel: [    3.333731] ------------[
cut here ]------------
2016-04-21T15:44:22.319064-07:00 WARNING kernel: [    3.333745] WARNING: CPU: 2
PID: 3111 at
/mnt/host/source/src/third_party/kernel/v3.14/drivers/gpu/drm/i915/i915_gem.c:5125
i915_gem_obj_to_ggtt+0x4b/0x4f()
2016-04-21T15:44:22.319069-07:00 NOTICE kernel: [    3.333756] Modules linked
in: nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables btusb btbcm
btintel bluetooth iio_trig_sysfs iwlmvm iwl7000_mac80211 snd_hda_codec_hdmi
iwlwifi cfg80211 snd_hda_intel snd_hda_controller snd_hda_codec cros_ec_accel
kfifo_buf snd_hwdep industrialio joydev snd_seq_midi snd_seq_midi_event
snd_rawmidi snd_seq snd_seq_device ppp_async ppp_generic slhc tun
2016-04-21T15:44:22.319072-07:00 NOTICE kernel: [    3.333818] CPU: 2 PID: 3111
Comm: CompositorTileW Not tainted 3.14.0 #1
2016-04-21T15:44:22.319073-07:00 NOTICE kernel: [    3.333825] Hardware name:
GOOGLE Samus, BIOS Google_Samus.6300.174.0 04/02/2015
2016-04-21T15:44:22.319075-07:00 NOTICE kernel: [    3.333832]  0000000000000000
0000000033aa9751 ffff880074c9dde8 ffffffff88da4cf3
2016-04-21T15:44:22.319077-07:00 NOTICE kernel: [    3.333842]  0000000000000000
ffff880074c9de20 ffffffff8883df6b ffffffff88aeb7e4
2016-04-21T15:44:22.319079-07:00 NOTICE kernel: [    3.333851]  ffff8802747c6f00
0000000000000000 ffff880274dd07c8 0000000040086200
2016-04-21T15:44:22.319080-07:00 NOTICE kernel: [    3.333861] Call Trace:
2016-04-21T15:44:22.319083-07:00 NOTICE kernel: [    3.333869] 
[<ffffffff88da4cf3>] dump_stack+0x4d/0x6f
2016-04-21T15:44:22.319084-07:00 NOTICE kernel: [    3.333877] 
[<ffffffff8883df6b>] warn_slowpath_common+0x7f/0x98
2016-04-21T15:44:22.319086-07:00 NOTICE kernel: [    3.333884] 
[<ffffffff88aeb7e4>] ? i915_gem_obj_to_ggtt+0x4b/0x4f
2016-04-21T15:44:22.319088-07:00 NOTICE kernel: [    3.333892] 
[<ffffffff8883e07d>] warn_slowpath_null+0x1a/0x1c
2016-04-21T15:44:22.319089-07:00 NOTICE kernel: [    3.333898] 
[<ffffffff88aeb7e4>] i915_gem_obj_to_ggtt+0x4b/0x4f
2016-04-21T15:44:22.319091-07:00 NOTICE kernel: [    3.333905] 
[<ffffffff88aeb8c8>] i915_gem_object_set_to_gtt_domain+0xe0/0x113
2016-04-21T15:44:22.319093-07:00 NOTICE kernel: [    3.333915] 
[<ffffffff88b3b548>] i915_gem_end_cpu_access+0x2e/0x42
2016-04-21T15:44:22.319095-07:00 NOTICE kernel: [    3.333923] 
[<ffffffff88b6d5b3>] dma_buf_end_cpu_access+0x3f/0x44
2016-04-21T15:44:22.319096-07:00 NOTICE kernel: [    3.333931] 
[<ffffffff88b6d8ac>] dma_buf_ioctl+0x8d/0xc5
2016-04-21T15:44:22.319098-07:00 NOTICE kernel: [    3.333938] 
[<ffffffff8891c708>] do_vfs_ioctl+0x355/0x416
2016-04-21T15:44:22.319100-07:00 NOTICE kernel: [    3.333945] 
[<ffffffff88924ec7>] ? __fget+0x6f/0x79
2016-04-21T15:44:22.319102-07:00 NOTICE kernel: [    3.333951] 
[<ffffffff8891c820>] SyS_ioctl+0x57/0x79
2016-04-21T15:44:22.319104-07:00 NOTICE kernel: [    3.333958] 
[<ffffffff88daa09c>] system_call_fastpath+0x20/0x25
2016-04-21T15:44:22.319105-07:00 WARNING kernel: [    3.333965] ---[ end trace
24f8672c7ed89e88 ]---

[dshwang, 2016-04-25 07:20:49]

Close as WontFix as warning is fixed in
https://chromium-review.googlesource.com/#/c/340480/

[dshwang, 2016-05-17 11:45:20]

Description was changed from

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=605774
==========

to

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=611968
==========

[dshwang, 2016-05-17 11:45:42]

dongseong.hwang@intel.com changed reviewers:
+ marcheu@chromium.org
- kalin@chromium.org, rookrishna@chromium.org

[dshwang, 2016-05-17 11:46:50]

Reopen this CL as i915_gem_end_cpu_access actually causes crash.

spang@, could you review?

[dshwang, 2016-05-17 11:47:05]

Description was changed from

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=611968
==========

to

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=611968, 612078
==========

[dshwang, 2016-05-17 11:48:28]

Description was changed from

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

The synchronization logic is for Atom, and we didn't enable GBMs on any Atom.
So we can comment it out until it's fixed.

BUG=611968, 612078
==========

to

==========
Ozone GBM: i915_gem_end_cpu_access causes crash.

Only Intel Atom architecture needs the synchronization logic, and we didn't
enable GBMs on any Atom devices.
So we can comment it out until it's fixed.

BUG=611968, 612078
==========

[marcheu1, 2016-05-17 15:29:21]

On 2016/05/17 11:46:50, dshwang wrote:
> Reopen this CL as i915_gem_end_cpu_access actually causes crash.
> 
> spang@, could you review?

Isn't this going to break correctness on non-coherent platforms at least?

[dshwang, 2016-05-17 16:45:13]

On 2016/05/17 15:29:21, marcheu1 wrote:
> On 2016/05/17 11:46:50, dshwang wrote:
> > Reopen this CL as i915_gem_end_cpu_access actually causes crash.
> > 
> > spang@, could you review?
> 
> Isn't this going to break correctness on non-coherent platforms at least?

It can break correctness on non-coherent platforms. However, as we enable it on
only coherent platform (i.e. Haswell, Broadwell and Skylake), it's fine now.
However, we have to fix the root issue later.