[PATCH] drm/msm/mdp5: use __drm_atomic_helper_plane_duplicate_state()

[Rob Clark]

On Wed, May 3, 2017 at 11:04 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Wed, May 03, 2017 at 10:40:36AM -0400, Rob Clark wrote:
>> Somehow the helper was never retrofitted for mdp5.  Which meant when
>> plane_state->fence was added, it could get copied into new state in
>> mdp5_plane_duplicate_state().
>>
>> If an update to disable the plane (for example on rmfb) managed to sneak
>> in after an nonblock update had swapped state, but before it was
>> committed, we'd get a splat:
>>
>>     WARNING: CPU: 1 PID: 69 at ../drivers/gpu/drm/drm_atomic_helper.c:1061 drm_atomic_helper_wait_for_fences+0xe0/0xf8
>>    Modules linked in:
>>
>>    CPU: 1 PID: 69 Comm: kworker/1:1 Tainted: G        W       4.11.0-rc8+ #1187
>>    Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
>>    Workqueue: events drm_mode_rmfb_work_fn
>>    task: ffffffc036560d00 task.stack: ffffffc036550000
>>    PC is at drm_atomic_helper_wait_for_fences+0xe0/0xf8
>>    LR is at complete_commit.isra.1+0x44/0x1c0
>>    pc : [<ffffff80084f6040>] lr : [<ffffff800854176c>] pstate: 20000145
>>    sp : ffffffc036553b60
>>    x29: ffffffc036553b60 x28: ffffffc0264e6a00
>>    x27: ffffffc035659000 x26: 0000000000000000
>>    x25: ffffffc0240e8000 x24: 0000000000000038
>>    x23: 0000000000000000 x22: ffffff800858f200
>>    x21: ffffffc0240e8000 x20: ffffffc02f56a800
>>    x19: 0000000000000000 x18: 0000000000000000
>>    x17: 0000000000000000 x16: 0000000000000000
>>    x15: 0000000000000000 x14: ffffffc00a192700
>>    x13: 0000000000000004 x12: 0000000000000000
>>    x11: ffffff80089a1690 x10: 00000000000008f0
>>    x9 : ffffffc036553b20 x8 : ffffffc036561650
>>    x7 : ffffffc03fe6cb40 x6 : 0000000000000000
>>    x5 : 0000000000000001 x4 : 0000000000000002
>>    x3 : ffffffc035659000 x2 : ffffffc0240e8c80
>>    x1 : 0000000000000000 x0 : ffffffc02adbe588
>>
>>    ---[ end trace 13aeec77c3fb55e2 ]---
>>    Call trace:
>>    Exception stack(0xffffffc036553990 to 0xffffffc036553ac0)
>>    3980:                                   0000000000000000 0000008000000000
>>    39a0: ffffffc036553b60 ffffff80084f6040 0000000000004ff0 0000000000000038
>>    39c0: ffffffc0365539d0 ffffff800857e098 ffffffc036553a00 ffffff800857e1b0
>>    39e0: ffffffc036553a10 ffffff800857c554 ffffffc0365e8400 ffffffc0365e8400
>>    3a00: ffffffc036553a20 ffffff8008103358 000000000001aad7 ffffff800851b72c
>>    3a20: ffffffc036553a50 ffffff80080e9228 ffffffc02adbe588 0000000000000000
>>    3a40: ffffffc0240e8c80 ffffffc035659000 0000000000000002 0000000000000001
>>    3a60: 0000000000000000 ffffffc03fe6cb40 ffffffc036561650 ffffffc036553b20
>>    3a80: 00000000000008f0 ffffff80089a1690 0000000000000000 0000000000000004
>>    3aa0: ffffffc00a192700 0000000000000000 0000000000000000 0000000000000000
>>    [<ffffff80084f6040>] drm_atomic_helper_wait_for_fences+0xe0/0xf8
>>    [<ffffff800854176c>] complete_commit.isra.1+0x44/0x1c0
>>    [<ffffff8008541c64>] msm_atomic_commit+0x32c/0x350
>>    [<ffffff8008516230>] drm_atomic_commit+0x50/0x60
>>    [<ffffff8008517548>] drm_atomic_remove_fb+0x158/0x250
>>    [<ffffff80085186d0>] drm_framebuffer_remove+0x50/0x158
>>    [<ffffff8008518818>] drm_mode_rmfb_work_fn+0x40/0x58
>>    [<ffffff80080d5668>] process_one_work+0x1d0/0x378
>>    [<ffffff80080d5a54>] worker_thread+0x244/0x488
>>    [<ffffff80080db7fc>] kthread+0xfc/0x128
>>    [<ffffff8008082ec0>] ret_from_fork+0x10/0x50
>>
>> Reported-by: Stanimir Varbanov <stanimir.varbanov at linaro.org>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>

I've also added:

Fixes: 9626014 ("drm/fence: add in-fences support")

(so folks know which stable branches it should end up in)

BR,
-R

> Oops, but does indeed explain what's going on.
>
> Cc: stable at vger.kernel.org
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
>> ---
>>  drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c
>> index a38c5fe..30b4691 100644
>> --- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c
>> +++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_plane.c
>> @@ -225,9 +225,10 @@ mdp5_plane_duplicate_state(struct drm_plane *plane)
>>
>>       mdp5_state = kmemdup(to_mdp5_plane_state(plane->state),
>>                       sizeof(*mdp5_state), GFP_KERNEL);
>> +     if (!mdp5_state)
>> +             return NULL;
>>
>> -     if (mdp5_state && mdp5_state->base.fb)
>> -             drm_framebuffer_reference(mdp5_state->base.fb);
>> +     __drm_atomic_helper_plane_duplicate_state(plane, &mdp5_state->base);
>>
>>       return &mdp5_state->base;
>>  }
>> --
>> 2.9.3
>>
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>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch