gpu: nvgpu: Remove early exit from mmu fault

Disabling / enabling of PFIFO must stay inside the isr.  It cannot be held
disabled outside the isr -- this causes any kind of preemption mechanism to
fail in the presence of an MMU fault until the channel resets the engine.

Bug 1791696

Change-Id: I16600a8571f6555262a75deb305c1d67eb29581a
Signed-off-by: Cory Perry <cperry@nvidia.com>
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1191026
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index 3dd7cb02..23a014d7 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -1407,6 +1407,9 @@ static bool gk20a_fifo_handle_mmu_fault(
 
                         /* handled during channel free */
                         g->fifo.deferred_reset_pending = true;
+                        gk20a_dbg(gpu_dbg_intr | gpu_dbg_gpu_dbg,
+                                   "sm debugger attached,"
+                                   " deferring channel recovery to channel free");
                 } else if (engine_id != ~0) {
                         was_reset = mutex_is_locked(&g->fifo.gr_reset_mutex);
                         mutex_lock(&g->fifo.gr_reset_mutex);
@@ -1456,14 +1459,6 @@ static bool gk20a_fifo_handle_mmu_fault(
                         gk20a_err(dev_from_gk20a(g), "couldn't locate channel for mmu fault");
         }
 
-        if (g->fifo.deferred_reset_pending) {
-                gk20a_dbg(gpu_dbg_intr | gpu_dbg_gpu_dbg, "sm debugger attached,"
-                           " deferring channel recovery to channel free");
-                /* clear interrupt */
-                gk20a_writel(g, fifo_intr_mmu_fault_id_r(), fault_id);
-                goto exit_enable;
-        }
-
         /* clear interrupt */
         gk20a_writel(g, fifo_intr_mmu_fault_id_r(), fault_id);
 
@@ -1476,7 +1471,6 @@ static bool gk20a_fifo_handle_mmu_fault(
                      gr_gpfifo_ctl_access_enabled_f() |
                      gr_gpfifo_ctl_semaphore_access_enabled_f());
 
-exit_enable:
         /* It is safe to enable ELPG again. */
         if (support_gk20a_pmu(g->dev) && g->elpg_enabled)
                 gk20a_pmu_enable_elpg(g);