[PATCH v2] drm/atomic_helper: add a flag for duplicating drm_private_obj state

[Shawn Guo]

On Sat, Jun 27, 2020 at 7:53 PM Shawn Guo <shawnguo at kernel.org> wrote:
>
> From: Shawn Guo <shawn.guo at linaro.org>
>
> The msm/mdp5 driver uses state of drm_private_obj as its global atomic
> state, which keeps the assignment of hwpipe to plane.  With
> drm_private_obj missing from duplicate state call in context of atomic
> suspend/resume helpers, mdp5 suspend works with no problem only for the
> very first time.  Any subsequent suspend will hit the following warning,
> because hwpipe assignment doesn't get duplicated for suspend state.
>
> $ echo mem > /sys/power/state
> [   38.111144] PM: suspend entry (deep)
> [   38.111185] PM: Syncing filesystems ... done.
> [   38.114630] Freezing user space processes ... (elapsed 0.001 seconds) done.
> [   38.115912] OOM killer disabled.
> [   38.115914] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
> [   38.122170] ------------[ cut here ]------------
> [   38.122212] WARNING: CPU: 0 PID: 1747 at drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c:145 mdp5_pipe_release+0x90/0xc0
> [   38.122215] Modules linked in:
> [   38.122222] CPU: 0 PID: 1747 Comm: sh Not tainted 4.19.107-00515-g9d5e4d7a33ed-dirty #323
> [   38.122224] Hardware name: Square, Inc. T2 Devkit (DT)
> [   38.122228] pstate: 40000005 (nZcv daif -PAN -UAO)
> [   38.122230] pc : mdp5_pipe_release+0x90/0xc0
> [   38.122233] lr : mdp5_pipe_release+0x90/0xc0
> [   38.122235] sp : ffff00000d13b7f0
> [   38.122236] x29: ffff00000d13b7f0 x28: 0000000000000000
> [   38.122240] x27: 0000000000000002 x26: ffff800079adce00
> [   38.122243] x25: ffff800079405200 x24: 0000000000000000
> [   38.122246] x23: ffff80007a78cc08 x22: ffff80007b1cc018
> [   38.122249] x21: ffff80007b1cc000 x20: ffff80007b317080
> [   38.122252] x19: ffff80007a78ce80 x18: 0000000000020000
> [   38.122255] x17: 0000000000000000 x16: 0000000000000000
> [   38.122258] x15: 00000000fffffff0 x14: ffff000008c3fb48
> [   38.122261] x13: ffff000008cdac4a x12: ffff000008c3f000
> [   38.122264] x11: 0000000000000000 x10: ffff000008cda000
> [   38.122267] x9 : 0000000000000000 x8 : ffff000008ce4a40
> [   38.122269] x7 : 0000000000000000 x6 : 0000000039ea41a9
> [   38.122272] x5 : 0000000000000000 x4 : 0000000000000000
> [   38.122275] x3 : ffffffffffffffff x2 : c7580c109cae4500
> [   38.122278] x1 : 0000000000000000 x0 : 0000000000000024
> [   38.122281] Call trace:
> [   38.122285]  mdp5_pipe_release+0x90/0xc0
> [   38.122288]  mdp5_plane_atomic_check+0x2c0/0x448
> [   38.122294]  drm_atomic_helper_check_planes+0xd0/0x208
> [   38.122298]  drm_atomic_helper_check+0x38/0xa8
> [   38.122302]  drm_atomic_check_only+0x3e8/0x630
> [   38.122305]  drm_atomic_commit+0x18/0x58
> [   38.122309]  __drm_atomic_helper_disable_all.isra.12+0x15c/0x1a8
> [   38.122312]  drm_atomic_helper_suspend+0x80/0xf0
> [   38.122316]  msm_pm_suspend+0x4c/0x70
> [   38.122320]  dpm_run_callback.isra.6+0x20/0x68
> [   38.122323]  __device_suspend+0x110/0x308
> [   38.122326]  dpm_suspend+0x100/0x1f0
> [   38.122329]  dpm_suspend_start+0x64/0x70
> [   38.122334]  suspend_devices_and_enter+0x110/0x500
> [   38.122336]  pm_suspend+0x268/0x2c0
> [   38.122339]  state_store+0x88/0x110
> [   38.122345]  kobj_attr_store+0x14/0x28
> [   38.122352]  sysfs_kf_write+0x3c/0x50
> [   38.122355]  kernfs_fop_write+0x118/0x1e0
> [   38.122360]  __vfs_write+0x30/0x168
> [   38.122363]  vfs_write+0xa4/0x1a8
> [   38.122366]  ksys_write+0x64/0xe8
> [   38.122368]  __arm64_sys_write+0x18/0x20
> [   38.122374]  el0_svc_common+0x6c/0x178
> [   38.122377]  el0_svc_compat_handler+0x1c/0x28
> [   38.122381]  el0_svc_compat+0x8/0x18
> [   38.122383] ---[ end trace 24145b7d8545345b ]---
> [   38.491552] Disabling non-boot CPUs ...
>
> Let's add a flag for duplicating the state of drm_private_obj and set
> the flag from msm/mdp5 driver, so that the problem can be fixed while
> other drivers using drm_private_obj stay unaffected.
>
> Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
> ---
> Changes for v2:
>  - Add a flag to duplicate the state of drm_private_obj conditionally,
>    so that other drivers using drm_private_obj stay unaffected.

Hi Daniel,

Are you okay with this version?

Shawn