gpu: nvgpu: increase sync-unmap timeout to 100ms

- sync-unmap timeout was observed intermittently. so doubled the timeout
  value.
- also check ref count after last round of sleep. The polling could
  succeed during the last sleep.
- fix error print on timeout.

Bug 200434475

Change-Id: If821dfaca9b86873711f436645523dc49a5eba34
Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1828562
Reviewed-by: svc-misra-checker <svc-misra-checker@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/gpu/nvgpu/common/mm/vm.c b/drivers/gpu/nvgpu/common/mm/vm.c
index 98bad70b..33587e5d 100644
--- a/drivers/gpu/nvgpu/common/mm/vm.c
+++ b/drivers/gpu/nvgpu/common/mm/vm.c
@@ -1179,9 +1179,9 @@ static int nvgpu_vm_unmap_sync_buffer(struct vm_gk20a *vm,
         nvgpu_mutex_release(&vm->update_gmmu_lock);
 
         /*
-         * 500ms second timer.
+         * 100ms timer.
          */
-        nvgpu_timeout_init(vm->mm->g, &timeout, 50, NVGPU_TIMER_CPU_TIMER);
+        nvgpu_timeout_init(vm->mm->g, &timeout, 100, NVGPU_TIMER_CPU_TIMER);
 
         do {
                 if (nvgpu_atomic_read(&mapped_buffer->ref.refcount) == 1) {
@@ -1189,9 +1189,11 @@ static int nvgpu_vm_unmap_sync_buffer(struct vm_gk20a *vm,
                 }
                 nvgpu_msleep(10);
         } while (nvgpu_timeout_expired_msg(&timeout,
-                            "sync-unmap failed on 0x%llx") == 0);
+                            "sync-unmap failed on 0x%llx",
+                            mapped_buffer->addr) == 0);
 
-        if (nvgpu_timeout_expired(&timeout)) {
+        if (nvgpu_atomic_read(&mapped_buffer->ref.refcount) != 1 &&
+                        nvgpu_timeout_expired(&timeout)) {
                 ret = -ETIMEDOUT;
         }