drm/radeon: Avoid double gpu reset by adding a timeout on IB ring tests.

When the radeon driver resets a gpu, it attempts to test whether all the
rings can successfully handle an IB.  If these rings fail to respond, the
process will wait forever.  Another gpu reset can't happen at this point,
as the current reset holds a lock required to do so.  Instead, make all
the IB tests run with a timeout, so the system can attempt to recover
in this case.

While this doesn't fix the underlying issue with card resets failing, it
gives the system a higher chance of recovering.  These timeouts have been
confirmed to help both a Tathi and Hawaii card recover after a gpu reset.

This also adds a new function, radeon_fence_wait_timeout, that behaves like
fence_wait_timeout.  It is used instead of fence_wait_timeout as it continues
to work during a reset.  radeon_fence_wait is changed to be implemented
using this function.

V2:
 - Changed the timeout to 1s, as the default 10s from radeon_wait_timeout was
too long.  A timeout of 100ms was tested and found to be too short.
 - Changed radeon_fence_wait_timeout to behave more like fence_wait_timeout.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

9 files changed, 89 insertions, 23 deletions

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index 4c30d8c65558..06001400ce8b 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -4219,13 +4219,20 @@ int cik_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		DRM_ERROR("radeon: failed to schedule ib (%d).\n", r);
 		return r;
 	}
-	r = radeon_fence_wait(ib.fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(ib.fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		radeon_scratch_free(rdev, scratch);
 		radeon_ib_free(rdev, &ib);
 		return r;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		radeon_scratch_free(rdev, scratch);
+		radeon_ib_free(rdev, &ib);
+		return -ETIMEDOUT;
 	}
+	r = 0;
 	for (i = 0; i < rdev->usec_timeout; i++) {
 		tmp = RREG32(scratch);
 		if (tmp == 0xDEADBEEF)
diff --git a/drivers/gpu/drm/radeon/cik_sdma.c b/drivers/gpu/drm/radeon/cik_sdma.c
index d16f2eebd95e..9c351dc8a9e0 100644
--- a/drivers/gpu/drm/radeon/cik_sdma.c
+++ b/drivers/gpu/drm/radeon/cik_sdma.c
@@ -737,11 +737,16 @@ int cik_sdma_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		DRM_ERROR("radeon: failed to schedule ib (%d).\n", r);
 		return r;
 	}
-	r = radeon_fence_wait(ib.fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(ib.fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		return r;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		return -ETIMEDOUT;
 	}
+	r = 0;
 	for (i = 0; i < rdev->usec_timeout; i++) {
 		tmp = le32_to_cpu(rdev->wb.wb[index/4]);
 		if (tmp == 0xDEADBEEF)
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 5eae0a88dd3e..6e478a248628 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -3732,11 +3732,17 @@ int r100_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		DRM_ERROR("radeon: failed to schedule ib (%d).\n", r);
 		goto free_ib;
 	}
-	r = radeon_fence_wait(ib.fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(ib.fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		goto free_ib;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		r = -ETIMEDOUT;
+		goto free_ib;
 	}
+	r = 0;
 	for (i = 0; i < rdev->usec_timeout; i++) {
 		tmp = RREG32(scratch);
 		if (tmp == 0xDEADBEEF) {
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index cc2fdf0be37a..ed121042247f 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -3381,11 +3381,17 @@ int r600_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		DRM_ERROR("radeon: failed to schedule ib (%d).\n", r);
 		goto free_ib;
 	}
-	r = radeon_fence_wait(ib.fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(ib.fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		goto free_ib;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		r = -ETIMEDOUT;
+		goto free_ib;
 	}
+	r = 0;
 	for (i = 0; i < rdev->usec_timeout; i++) {
 		tmp = RREG32(scratch);
 		if (tmp == 0xDEADBEEF)
diff --git a/drivers/gpu/drm/radeon/r600_dma.c b/drivers/gpu/drm/radeon/r600_dma.c
index d2dd29ab24fa..fb65e6fb5c4f 100644
--- a/drivers/gpu/drm/radeon/r600_dma.c
+++ b/drivers/gpu/drm/radeon/r600_dma.c
@@ -368,11 +368,16 @@ int r600_dma_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		DRM_ERROR("radeon: failed to schedule ib (%d).\n", r);
 		return r;
 	}
-	r = radeon_fence_wait(ib.fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(ib.fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		return r;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		return -ETIMEDOUT;
 	}
+	r = 0;
 	for (i = 0; i < rdev->usec_timeout; i++) {
 		tmp = le32_to_cpu(rdev->wb.wb[index/4]);
 		if (tmp == 0xDEADBEEF)
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 78a51b3eda10..007be29a0020 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -120,6 +120,7 @@ extern int radeon_mst;
  */
 #define RADEON_MAX_USEC_TIMEOUT			100000	/* 100 ms */
 #define RADEON_FENCE_JIFFIES_TIMEOUT		(HZ / 2)
+#define RADEON_USEC_IB_TEST_TIMEOUT		1000000 /* 1s */
 /* RADEON_IB_POOL_SIZE must be a power of 2 */
 #define RADEON_IB_POOL_SIZE			16
 #define RADEON_DEBUGFS_MAX_COMPONENTS		32
@@ -382,6 +383,7 @@ void radeon_fence_driver_force_completion(struct radeon_device *rdev, int ring);
 int radeon_fence_emit(struct radeon_device *rdev, struct radeon_fence **fence, int ring);
 void radeon_fence_process(struct radeon_device *rdev, int ring);
 bool radeon_fence_signaled(struct radeon_fence *fence);
+long radeon_fence_wait_timeout(struct radeon_fence *fence, bool interruptible, long timeout);
 int radeon_fence_wait(struct radeon_fence *fence, bool interruptible);
 int radeon_fence_wait_next(struct radeon_device *rdev, int ring);
 int radeon_fence_wait_empty(struct radeon_device *rdev, int ring);
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index 05815c47b246..7ef075acde9c 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -527,7 +527,7 @@ static long radeon_fence_wait_seq_timeout(struct radeon_device *rdev,
 }
 
 /**
- * radeon_fence_wait - wait for a fence to signal
+ * radeon_fence_wait_timeout - wait for a fence to signal with timeout
  *
  * @fence: radeon fence object
  * @intr: use interruptible sleep
@@ -535,12 +535,15 @@ static long radeon_fence_wait_seq_timeout(struct radeon_device *rdev,
  * Wait for the requested fence to signal (all asics).
  * @intr selects whether to use interruptable (true) or non-interruptable
  * (false) sleep when waiting for the fence.
- * Returns 0 if the fence has passed, error for all other cases.
+ * @timeout: maximum time to wait, or MAX_SCHEDULE_TIMEOUT for infinite wait
+ * Returns remaining time if the sequence number has passed, 0 when
+ * the wait timeout, or an error for all other cases.
  */
-int radeon_fence_wait(struct radeon_fence *fence, bool intr)
+long radeon_fence_wait_timeout(struct radeon_fence *fence, bool intr, long timeout)
 {
 	uint64_t seq[RADEON_NUM_RINGS] = {};
 	long r;
+	int r_sig;
 
 	/*
 	 * This function should not be called on !radeon fences.
@@ -552,15 +555,36 @@ int radeon_fence_wait(struct radeon_fence *fence, bool intr)
 		return fence_wait(&fence->base, intr);
 
 	seq[fence->ring] = fence->seq;
-	r = radeon_fence_wait_seq_timeout(fence->rdev, seq, intr, MAX_SCHEDULE_TIMEOUT);
-	if (r < 0) {
+	r = radeon_fence_wait_seq_timeout(fence->rdev, seq, intr, timeout);
+	if (r <= 0) {
 		return r;
 	}
 
-	r = fence_signal(&fence->base);
-	if (!r)
+	r_sig = fence_signal(&fence->base);
+	if (!r_sig)
 		FENCE_TRACE(&fence->base, "signaled from fence_wait\n");
-	return 0;
+	return r;
+}
+
+/**
+ * radeon_fence_wait - wait for a fence to signal
+ *
+ * @fence: radeon fence object
+ * @intr: use interruptible sleep
+ *
+ * Wait for the requested fence to signal (all asics).
+ * @intr selects whether to use interruptable (true) or non-interruptable
+ * (false) sleep when waiting for the fence.
+ * Returns 0 if the fence has passed, error for all other cases.
+ */
+int radeon_fence_wait(struct radeon_fence *fence, bool intr)
+{
+	long r = radeon_fence_wait_timeout(fence, intr, MAX_SCHEDULE_TIMEOUT);
+	if (r > 0) {
+		return 0;
+	} else {
+		return r;
+	}
 }
 
 /**
diff --git a/drivers/gpu/drm/radeon/radeon_vce.c b/drivers/gpu/drm/radeon/radeon_vce.c
index 7eb1ae758906..566a1a01f6d1 100644
--- a/drivers/gpu/drm/radeon/radeon_vce.c
+++ b/drivers/gpu/drm/radeon/radeon_vce.c
@@ -810,11 +810,16 @@ int radeon_vce_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		goto error;
 	}
 
-	r = radeon_fence_wait(fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		r = -ETIMEDOUT;
 	} else {
-	        DRM_INFO("ib test on ring %d succeeded\n", ring->idx);
+		DRM_INFO("ib test on ring %d succeeded\n", ring->idx);
+		r = 0;
 	}
 error:
 	radeon_fence_unref(&fence);
diff --git a/drivers/gpu/drm/radeon/uvd_v1_0.c b/drivers/gpu/drm/radeon/uvd_v1_0.c
index c6b1cbca47fc..12ddcfa82e20 100644
--- a/drivers/gpu/drm/radeon/uvd_v1_0.c
+++ b/drivers/gpu/drm/radeon/uvd_v1_0.c
@@ -522,11 +522,17 @@ int uvd_v1_0_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
 		goto error;
 	}
 
-	r = radeon_fence_wait(fence, false);
-	if (r) {
+	r = radeon_fence_wait_timeout(fence, false, usecs_to_jiffies(
+		RADEON_USEC_IB_TEST_TIMEOUT));
+	if (r < 0) {
 		DRM_ERROR("radeon: fence wait failed (%d).\n", r);
 		goto error;
+	} else if (r == 0) {
+		DRM_ERROR("radeon: fence wait timed out.\n");
+		r = -ETIMEDOUT;
+		goto error;
 	}
+	r = 0;
 	DRM_INFO("ib test on ring %d succeeded\n",  ring->idx);
 error:
 	radeon_fence_unref(&fence);