drm/imagination: Fix kernel crash when hard resetting the GPU

The GPU hard reset sequence calls pm_runtime_force_suspend() and
pm_runtime_force_resume(), which according to their documentation should
only be used during system-wide PM transitions to sleep states.

The main issue though is that depending on some internal runtime PM
state as seen by pm_runtime_force_suspend() (whether the usage count is
<= 1), pm_runtime_force_resume() might not resume the device unless
needed. If that happens, the runtime PM resume callback
pvr_power_device_resume() is not called, the GPU clocks are not
re-enabled, and the kernel crashes on the next attempt to access GPU
registers as part of the power-on sequence.

Replace calls to pm_runtime_force_suspend() and
pm_runtime_force_resume() with direct calls to the driver's runtime PM
callbacks, pvr_power_device_suspend() and pvr_power_device_resume(),
to ensure clocks are re-enabled and avoid the kernel crash.

Fixes: cc1aeedb98ad ("drm/imagination: Implement firmware infrastructure and META FW support")
Signed-off-by: Alessio Belle <alessio.belle@imgtec.com>
Reviewed-by: Matt Coster <matt.coster@imgtec.com>
Link: https://lore.kernel.org/r/20250624-fix-kernel-crash-gpu-hard-reset-v1-1-6d24810d72a6@imgtec.com
Cc: stable@vger.kernel.org
Signed-off-by: Matt Coster <matt.coster@imgtec.com>

diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
index 41f5d89e78b854cf6993838868a4416a220b490a..3e349d039fc0c4176b5c4baf009ffa005a2b28d1 100644 (file)
--- a/drivers/gpu/drm/imagination/pvr_power.c
+++ b/drivers/gpu/drm/imagination/pvr_power.c
@@ -386,13 +386,13 @@ pvr_power_reset(struct pvr_device *pvr_dev, bool hard_reset)
                if (!err) {
                        if (hard_reset) {
                                pvr_dev->fw_dev.booted = false;
-                               WARN_ON(pm_runtime_force_suspend(from_pvr_device(pvr_dev)->dev));
+                               WARN_ON(pvr_power_device_suspend(from_pvr_device(pvr_dev)->dev));
 
                                err = pvr_fw_hard_reset(pvr_dev);
                                if (err)
                                        goto err_device_lost;
 
-                               err = pm_runtime_force_resume(from_pvr_device(pvr_dev)->dev);
+                               err = pvr_power_device_resume(from_pvr_device(pvr_dev)->dev);
                                pvr_dev->fw_dev.booted = true;
                                if (err)
                                        goto err_device_lost;