When the runtime PM resume callback returns an error, it puts the device in a state where it can't be resumed anymore. Make sure we can recover from such transient failures by calling pm_runtime_set_suspended() explicitly after a pm_runtime_resume_and_get() failure.
v3: - Add R-b/A-b v2: - Add a comment explaining potential races in panthor_device_resume_and_get() Signed-off-by: Boris Brezillon <[email protected]> Reviewed-by: Adrian Larumbe <[email protected]> Acked-by: Steven Price <[email protected]> --- drivers/gpu/drm/panthor/panthor_device.c | 1 + drivers/gpu/drm/panthor/panthor_device.h | 26 ++++++++++++++++++++++++ drivers/gpu/drm/panthor/panthor_drv.c | 2 +- drivers/gpu/drm/panthor/panthor_sched.c | 4 ++-- 4 files changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c index e3b22107b268..0362101ea896 100644 --- a/drivers/gpu/drm/panthor/panthor_device.c +++ b/drivers/gpu/drm/panthor/panthor_device.c @@ -500,6 +500,7 @@ int panthor_device_resume(struct device *dev) err_set_suspended: atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED); + atomic_set(&ptdev->pm.recovery_needed, 1); return ret; } diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h index 0e68f5a70d20..b6c4f25a5d6e 100644 --- a/drivers/gpu/drm/panthor/panthor_device.h +++ b/drivers/gpu/drm/panthor/panthor_device.h @@ -9,6 +9,7 @@ #include <linux/atomic.h> #include <linux/io-pgtable.h> #include <linux/regulator/consumer.h> +#include <linux/pm_runtime.h> #include <linux/sched.h> #include <linux/spinlock.h> @@ -180,6 +181,9 @@ struct panthor_device { * is suspended. */ struct page *dummy_latest_flush; + + /** @recovery_needed: True when a resume attempt failed. */ + atomic_t recovery_needed; } pm; /** @profile_mask: User-set profiling flags for job accounting. */ @@ -243,6 +247,28 @@ int panthor_device_mmap_io(struct panthor_device *ptdev, int panthor_device_resume(struct device *dev); int panthor_device_suspend(struct device *dev); +static inline int panthor_device_resume_and_get(struct panthor_device *ptdev) +{ + int ret = pm_runtime_resume_and_get(ptdev->base.dev); + + /* If the resume failed, we need to clear the runtime_error, which + * can done by forcing the RPM state to suspended. If multiple + * threads called panthor_device_resume_and_get(), we only want + * one of them to update the state, hence the cmpxchg. Note that a + * thread might enter panthor_device_resume_and_get() and call + * pm_runtime_resume_and_get() after another thread had attempted + * to resume and failed. This means we will end up with an error + * without even attempting a resume ourselves. The only risk here + * is to report an error when the second resume attempt might have + * succeeded. Given resume errors are not expected, this is probably + * something we can live with. + */ + if (ret && atomic_cmpxchg(&ptdev->pm.recovery_needed, 1, 0) == 1) + pm_runtime_set_suspended(ptdev->base.dev); + + return ret; +} + enum drm_panthor_exception_type { DRM_PANTHOR_EXCEPTION_OK = 0x00, DRM_PANTHOR_EXCEPTION_TERMINATED = 0x04, diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c index 1498c97b4b85..b7a9adc918e3 100644 --- a/drivers/gpu/drm/panthor/panthor_drv.c +++ b/drivers/gpu/drm/panthor/panthor_drv.c @@ -763,7 +763,7 @@ static int panthor_query_timestamp_info(struct panthor_device *ptdev, { int ret; - ret = pm_runtime_resume_and_get(ptdev->base.dev); + ret = panthor_device_resume_and_get(ptdev); if (ret) return ret; diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 97ed5fe5a191..77b184c3fb0c 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -2364,7 +2364,7 @@ static void tick_work(struct work_struct *work) if (!drm_dev_enter(&ptdev->base, &cookie)) return; - ret = pm_runtime_resume_and_get(ptdev->base.dev); + ret = panthor_device_resume_and_get(ptdev); if (drm_WARN_ON(&ptdev->base, ret)) goto out_dev_exit; @@ -3131,7 +3131,7 @@ queue_run_job(struct drm_sched_job *sched_job) return dma_fence_get(job->done_fence); } - ret = pm_runtime_resume_and_get(ptdev->base.dev); + ret = panthor_device_resume_and_get(ptdev); if (drm_WARN_ON(&ptdev->base, ret)) return ERR_PTR(ret); -- 2.47.0
