drm/radeon/kms: simplify & improve GPU reset V2

This simplify and improve GPU reset for R1XX-R6XX hw, it's
not 100% reliable here are result:
- R1XX/R2XX works bunch of time in a row, sometimes it
  seems it can work indifinitly
- R3XX/R3XX the most unreliable one, sometimes you will be
  able to reset few times, sometimes not even once
- R5XX more reliable than previous hw, seems to work most
  of the times but once in a while it fails for no obvious
  reasons (same status than previous reset just no same
  happy ending)
- R6XX/R7XX are lot more reliable with this patch, still
  it seems that it can fail after a bunch (reset every
  2sec for 3hour bring down the GPU & computer)

This have been tested on various hw, for some odd reasons
i wasn't able to lockup RS480/RS690 (while they use to
love locking up).

Note that on R1XX-R5XX the cursor will disapear after
lockup haven't checked why, switch to console and back
to X will restore cursor.

Next step is to record the bogus command that leaded to
the lockup.

V2 Fix r6xx resume path to avoid reinitializing blit
module, use the gpu_lockup boolean to avoid entering
inifinite waiting loop on fence while reiniting the GPU

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index 2560740ff922..fcd7802d8a71 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -209,8 +209,9 @@ retry:
                 r = wait_event_interruptible_timeout(rdev->fence_drv.queue,
                                 radeon_fence_signaled(fence), timeout);
                 radeon_irq_kms_sw_irq_put(rdev);
-                if (unlikely(r < 0))
+                if (unlikely(r < 0)) {
                         return r;
+                }
         } else {
                 radeon_irq_kms_sw_irq_get(rdev);
                 r = wait_event_timeout(rdev->fence_drv.queue,
@@ -230,14 +231,16 @@ retry:
                  */
                 if (seq == rdev->fence_drv.last_seq && radeon_gpu_is_lockup(rdev)) {
                         /* good news we believe it's a lockup */
-                        dev_warn(rdev->dev, "GPU lockup (last fence id 0x%08X)\n", seq);
-                        r = radeon_asic_reset(rdev);
-                        if (r)
-                                return r;
+                        WARN(1, "GPU lockup (waiting for 0x%08X last fence id 0x%08X)\n", fence->seq, seq);
                         /* FIXME: what should we do ? marking everyone
                          * as signaled for now
                          */
+                        rdev->gpu_lockup = true;
                         WREG32(rdev->fence_drv.scratch_reg, fence->seq);
+                        r = radeon_gpu_reset(rdev);
+                        if (r)
+                                return r;
+                        rdev->gpu_lockup = false;
                 }
                 timeout = RADEON_FENCE_JIFFIES_TIMEOUT;
                 write_lock_irqsave(&rdev->fence_drv.lock, irq_flags);