drm/radeon/kms: r600 handle irq vector ring overflow

In some rare case i faced an irq overflow quickly followed by
a GPU lockup (hard hang) this patch try to deal with irq vector
ring overflow, so far haven't been able to reproduce it with
the patch.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 0f9a8c6788a3..bb9115bdc3a2 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2648,9 +2648,13 @@ static inline u32 r600_get_ih_wptr(struct radeon_device *rdev)
         wptr = RREG32(IH_RB_WPTR);
 
         if (wptr & RB_OVERFLOW) {
-                WARN_ON(1);
-                /* XXX deal with overflow */
-                DRM_ERROR("IH RB overflow\n");
+                /* When a ring buffer overflow happen start parsing interrupt
+                 * from the last not overwritten vector (wptr + 16). Hopefully
+                 * this should allow us to catchup.
+                 */
+                dev_warn(rdev->dev, "IH ring buffer overflow (0x%08X, %d, %d)\n",
+                        wptr, rdev->ih.rptr, (wptr + 16) + rdev->ih.ptr_mask);
+                rdev->ih.rptr = (wptr + 16) & rdev->ih.ptr_mask;
                 tmp = RREG32(IH_RB_CNTL);
                 tmp |= IH_WPTR_OVERFLOW_CLEAR;
                 WREG32(IH_RB_CNTL, tmp);