drm/msm/a3xx: Drain VBIF before GPU suspend

A3xx hangs after every runtime suspend on the Samsung Galaxy S4
GT-I9505. Even simple GPU workloads, such as drawing a single triangle,
hang reliably once the GPU has been suspended by runtime PM.

The generic MSM GPU suspend path disables clocks/power, but A3xx also
needs to ensure that pending VBIF transactions are drained before that
happens.

Add an A3xx-specific pm_suspend callback. Wait for the GPU to become
idle, halt all VBIF XIN clients, wait for the corresponding
acknowledgment, and only then enter the generic MSM GPU suspend path.

This fixes reliable A3xx GPU hangs observed after runtime PM on the
Samsung Galaxy S4 GT-I9505, codename jflte. The failure is reported as:

  mdp4 5100000.display-controller: [drm:hangcheck_handler] *ERROR* 3.2.0.2: hangcheck detected gpu lockup rb 0!
  mdp4 5100000.display-controller: [drm:hangcheck_handler] *ERROR* 3.2.0.2:     completed fence: 4294967041
  mdp4 5100000.display-controller: [drm:hangcheck_handler] *ERROR* 3.2.0.2:     submitted fence: 4294967049
  mdp4 5100000.display-controller: [drm:recover_worker] *ERROR* 3.2.0.2: hangcheck recover!

Link: https://github.com/freedreno-zz/freedreno/issues/12
Signed-off-by: Alexandre MINETTE <contact@alex-min.fr>
Patchwork: https://patchwork.freedesktop.org/patch/731919/
Message-ID: <20260610-mainline-fix-a3xx-gpu-hang-sending-v1-1-9282182840b5@alex-min.fr>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions