[0/5] drm/panthor: Be robust against failures in the resume path

Message

Boris Brezillon Nov. 13, 2024, 3:42 p.m. UTC

Hello,

Here's a collection of patches improving robustness to failures in
the device resume/suspend path. Those failures are pretty hard to
reproduce (happens once in a while on a deqp-vk run), so I used a
mechanism to fake them.

Faking a FW boot failure is kinda tricky though, which means the
last patch has only been partially tested:
- the fast reset path is well tested because that's the default on
  a device suspend
- the slow reset has been tested with a hack replacing fast resets
  by slow resets
- the fast -> slow reset fallback has been tested by faking boot
  failures after a fast reset, but these are not real, which means
  we can't really validate if the MCU recovers fine after a slow
  reset

On the other hand, this implementation doesn't look like it could
do more harm than the current one (the only difference is the
extra GPU soft-reset that happens between the fast and slow FW
boot).

Regards,

Boris

Boris Brezillon (5):
  drm/panthor: Preserve the result returned by panthor_fw_resume()
  drm/panthor: Be robust against runtime PM resume failures in the
    suspend path
  drm/panthor: Ignore devfreq_{suspend,resume}_device() failures
  drm/panthor: Be robust against resume failures
  drm/panthor: Fix the fast-reset logic

 drivers/gpu/drm/panthor/panthor_devfreq.c | 12 ++--
 drivers/gpu/drm/panthor/panthor_devfreq.h |  4 +-
 drivers/gpu/drm/panthor/panthor_device.c  | 78 +++++++++++------------
 drivers/gpu/drm/panthor/panthor_device.h  | 28 ++++++++
 drivers/gpu/drm/panthor/panthor_drv.c     |  2 +-
 drivers/gpu/drm/panthor/panthor_fw.c      | 62 +++++-------------
 drivers/gpu/drm/panthor/panthor_gpu.c     | 14 ++--
 drivers/gpu/drm/panthor/panthor_mmu.c     |  3 +-
 drivers/gpu/drm/panthor/panthor_sched.c   |  4 +-
 9 files changed, 102 insertions(+), 105 deletions(-)