[PATCH 53/59] drm/arc: Move to drm/tiny

[Eugeniy Paltsev]

So, I've smoke tested it. Though it is working, it's really unstable and causes kernel crash in many cases.

I.e:
This kernel crash (due to invalid read in kernel mode by 0x0000007c address) happens
on HDMI cable disconnection:
----------------------------------->8-------------------------------------------
Oops
Path: (null)
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.7.0-rc6-03007-g4ceda91a4176 #5
Workqueue: events adv7511_hpd_work
Invalid Read @ 0x0000007c by insn @ drm_gem_fb_get_obj+0xa/0x10
ECR: 0x00050100 EFA: 0x0000007c ERET: 0x813b954a
STAT32: 0x80080442 [IE K DE   ]  BTA: 0x813eef62
BLK: arc_pgu_update+0x1a/0x30
 SP: 0x9f055dd0  FP: 0x00000000
LPS: 0x8135603c LPE: 0x81356044 LPC: 0x00000000
r00: 0x00000000 r01: 0x00000000 r02: 0x9f6bc000
r03: 0x9f0d8000 r04: 0x9f0d8388 r05: 0x00000000
r06: 0x00000000 r07: 0x00000000 r08: 0x00000000
r09: 0x00000000 r10: 0x00000000 r11: 0x00000000
r12: 0x813eef62

Stack Trace:
  drm_gem_fb_get_obj+0xa/0x10
  arc_pgu_update+0x1a/0x30
  drm_atomic_helper_commit_planes.constprop.35+0xc8/0x23c
  commit_tail+0x164/0x274
  drm_atomic_helper_commit+0x36a/0x398
  drm_client_modeset_commit_atomic+0x136/0x1a4
  drm_client_modeset_commit_locked+0x3a/0x118
  drm_client_modeset_commit+0x18/0x34
  drm_fb_helper_set_par+0x54/0xb0
  drm_fb_helper_hotplug_event.part.16+0x70/0x8c
  drm_client_dev_hotplug+0x4a/0x74
  adv7511_hpd_work+0x6c/0x124
  process_one_work+0x19a/0x358
  worker_thread+0x108/0x494
  kthread+0xec/0x100
  ret_from_fork+0x18/0x1c
----------------------------------->8-------------------------------------------


This kernel crash (due to invalid read in kernel mode by 0x0 address) happens
on weston stop:
----------------------------------->8-------------------------------------------
Oops
Path: (null)
CPU: 0 PID: 158 Comm: weston Not tainted 5.7.0-rc6-03007-g4ceda91a4176 #5
Invalid Read @ 0x00000000 by insn @ drm_gem_fb_destroy+0x32/0x130
ECR: 0x00050100 EFA: 0x00000000 ERET: 0x813b9a76
STAT32: 0x80080002 [IE K     ]  BTA: 0x81345c66
BLK: drm_fb_release+0x66/0xb0
 SP: 0x9f5c7db8  FP: 0x5fa4fa7c
LPS: 0x813560ec LPE: 0x813560f0 LPC: 0x00000000
r00: 0x00000000 r01: 0x9e864392 r02: 0x00000002
r03: 0x00000001 r04: 0x00000026 r05: 0x00000000
r06: 0x00000114 r07: 0x00000001 r08: 0x9f0d8140
r09: 0xfffffe20 r10: 0x30405c00 r11: 0x00000039
r12: 0x813d6c16 r13: 0x00022cc8 r14: 0xffffffff
r15: 0x00023ef0 r16: 0x5fa4f874 r17: 0x00022c58
r18: 0x5fa4fde4 r19: 0x00000000 r20: 0x000203c0
r21: 0x00000000 r22: 0x00022d40 r23: 0xffffffff
r24: 0x5fa4fa80 r25: 0x2000b808



Stack Trace:
  drm_gem_fb_destroy+0x32/0x130
  drm_fb_release+0x66/0xb0
  drm_file_free.part.11+0x112/0x1bc
  drm_release+0x80/0x120
  __fput+0x98/0x1bc
  task_work_run+0x6e/0xa8
  do_exit+0x2b4/0x7fc
  do_group_exit+0x2a/0x8c
  get_signal+0x9a/0x5f0
  do_signal+0x86/0x23c
  resume_user_mode_begin+0x88/0xd0

----------------------------------->8-------------------------------------------

It was tested on AXS103 board with ARC PGU + adv7511 HDMI bridge.

Probably you have some ideas about how to fix it?
Thanks.



> From: Daniel Vetter <daniel at ffwll.ch>
> Sent: Monday, May 25, 2020 20:26
> To: Eugeniy Paltsev
> Cc: dri-devel
> Subject: Re: [PATCH 53/59] drm/arc: Move to drm/tiny
> 
> On Mon, May 25, 2020 at 6:36 PM Eugeniy Paltsev
> <Eugeniy.Paltsev at synopsys.com> wrote:
> >
> > Hi Daniel,
> >
> > looks like I'll finally have some time for review of "drm/arc: Move to drm/tiny".
> > So, is it possible to find all these changes in any public git repo?
> 
> I have a horrible pile with everything here:
> 
> https://urldefense.com/v3/__https://cgit.freedesktop.org/*danvet/drm/log/__;fg!!A4F2R9G_pg!KUgdCRZoVj_85WhtTr0NUhsLhDgVTN_7s2aNdS4mMmRDfstvp4JbIYdip4J0P3Hg1NQLG2E$
> 
> I can also give you a cherry-picked branch with just the arc patches,
> on drm-tip (maybe also linux-next, not sure everything is there
> because of the merge window freeze we're in already).
> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - https://urldefense.com/v3/__http://blog.ffwll.ch__;!!A4F2R9G_pg!KUgdCRZoVj_85WhtTr0NUhsLhDgVTN_7s2aNdS4mMmRDfstvp4JbIYdip4J0P3HgteJOwjA$