drm/radeon: avoid deadlock in pm path when waiting for fence

radeon_fence_wait_empty_locked should not trigger GPU reset as no
place where it's call from would benefit from such thing and it
actually lead to a kernel deadlock in case the reset is triggered
from pm codepath. Instead force ring completion in place where it
makes sense or return early in others.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index aae7314..9b9422c 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -231,7 +231,7 @@ void radeon_fence_process(struct radeon_device *rdev, int ring);
 bool radeon_fence_signaled(struct radeon_fence *fence);
 int radeon_fence_wait(struct radeon_fence *fence, bool interruptible);
 int radeon_fence_wait_next_locked(struct radeon_device *rdev, int ring);
-void radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring);
+int radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring);
 int radeon_fence_wait_any(struct radeon_device *rdev,
                          struct radeon_fence **fences,
                          bool intr);

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index e81d6ca..a6617b5 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1164,6 +1164,7 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state)
        struct drm_crtc *crtc;
        struct drm_connector *connector;
        int i, r;
+       bool force_completion = false;
 
        if (dev == NULL || dev->dev_private == NULL) {
                return -ENODEV;
@@ -1206,8 +1207,16 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state)
 
        mutex_lock(&rdev->ring_lock);
        /* wait for gpu to finish processing current batch */
-       for (i = 0; i < RADEON_NUM_RINGS; i++)
-               radeon_fence_wait_empty_locked(rdev, i);
+       for (i = 0; i < RADEON_NUM_RINGS; i++) {
+               r = radeon_fence_wait_empty_locked(rdev, i);
+               if (r) {
+                       /* delay GPU reset to resume */
+                       force_completion = true;
+               }
+       }
+       if (force_completion) {
+               radeon_fence_driver_force_completion(rdev);
+       }
        mutex_unlock(&rdev->ring_lock);
 
        radeon_save_bios_scratch_regs(rdev);

diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index a9b0fa5..3435625 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -609,26 +609,20 @@ int radeon_fence_wait_next_locked(struct radeon_device *rdev, int ring)
  * Returns 0 if the fences have passed, error for all other cases.
  * Caller must hold ring lock.
  */
-void radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring)
+int radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring)
 {
        uint64_t seq = rdev->fence_drv[ring].sync_seq[ring];
+       int r;
 
-       while(1) {
-               int r;
-               r = radeon_fence_wait_seq(rdev, seq, ring, false, false);
+       r = radeon_fence_wait_seq(rdev, seq, ring, false, false);
+       if (r) {
                if (r == -EDEADLK) {
-                       mutex_unlock(&rdev->ring_lock);
-                       r = radeon_gpu_reset(rdev);
-                       mutex_lock(&rdev->ring_lock);
-                       if (!r)
-                               continue;
-               }
-               if (r) {
-                       dev_err(rdev->dev, "error waiting for ring to become"
-                               " idle (%d)\n", r);
+                       return -EDEADLK;
                }
-               return;
+               dev_err(rdev->dev, "error waiting for ring[%d] to become idle (%d)\n",
+                       ring, r);
        }
+       return 0;
 }
 
 /**
@@ -854,13 +848,17 @@ int radeon_fence_driver_init(struct radeon_device *rdev)
  */
 void radeon_fence_driver_fini(struct radeon_device *rdev)
 {
-       int ring;
+       int ring, r;
 
        mutex_lock(&rdev->ring_lock);
        for (ring = 0; ring < RADEON_NUM_RINGS; ring++) {
                if (!rdev->fence_drv[ring].initialized)
                        continue;
-               radeon_fence_wait_empty_locked(rdev, ring);
+               r = radeon_fence_wait_empty_locked(rdev, ring);
+               if (r) {
+                       /* no need to trigger GPU reset as we are unloading */
+                       radeon_fence_driver_force_completion(rdev);
+               }
                wake_up_all(&rdev->fence_queue);
                radeon_scratch_free(rdev, rdev->fence_drv[ring].scratch_reg);
                rdev->fence_drv[ring].initialized = false;

diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index aa14dbb..0bfa656 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -234,7 +234,7 @@ static void radeon_set_power_state(struct radeon_device *rdev)
 
 static void radeon_pm_set_clocks(struct radeon_device *rdev)
 {
-       int i;
+       int i, r;
 
        /* no need to take locks, etc. if nothing's going to change */
        if ((rdev->pm.requested_clock_mode_index == rdev->pm.current_clock_mode_index) &&
@@ -248,8 +248,17 @@ static void radeon_pm_set_clocks(struct radeon_device *rdev)
        /* wait for the rings to drain */
        for (i = 0; i < RADEON_NUM_RINGS; i++) {
                struct radeon_ring *ring = &rdev->ring[i];
-               if (ring->ready)
-                       radeon_fence_wait_empty_locked(rdev, i);
+               if (!ring->ready) {
+                       continue;
+               }
+               r = radeon_fence_wait_empty_locked(rdev, i);
+               if (r) {
+                       /* needs a GPU reset dont reset here */
+                       mutex_unlock(&rdev->ring_lock);
+                       up_write(&rdev->pm.mclk_lock);
+                       mutex_unlock(&rdev->ddev->struct_mutex);
+                       return;
+               }
        }
 
        radeon_unmap_vram_bos(rdev);