gpu: nvgpu: ring doorbell after enabling TSG

In some use cases client will disable and preempt TSG and then re-enable it
using IOCTLs provided

In case there is only one context getting re-enabled and there is no other job
submission in parallel runlist fetcher will just sleep until doorbell is
received next time

This causes above mentioned test cases to stall after re-enabling TSG until
some one submits a new job and triggers a doorbell

Fix this by explicitly triggering doorbell from gv11b_fifo_enable_tsg() after
we enable all channels in TSG

Bug 2205192

Change-Id: I08e70e3d0f7e4dc6471e63809e246430cc4200c1
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1772378
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@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, 5 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gv11b/fifo_gv11b.c b/drivers/gpu/nvgpu/gv11b/fifo_gv11b.c
index 9c64675f..75ff9525 100644
--- a/drivers/gpu/nvgpu/gv11b/fifo_gv11b.c
+++ b/drivers/gpu/nvgpu/gv11b/fifo_gv11b.c
@@ -808,13 +808,18 @@ int gv11b_fifo_enable_tsg(struct tsg_gk20a *tsg)
 {
         struct gk20a *g = tsg->g;
         struct channel_gk20a *ch;
+        struct channel_gk20a *last_ch = NULL;
 
         nvgpu_rwsem_down_read(&tsg->ch_list_lock);
         nvgpu_list_for_each_entry(ch, &tsg->ch_list, channel_gk20a, ch_entry) {
                 g->ops.fifo.enable_channel(ch);
+                last_ch = ch;
         }
         nvgpu_rwsem_up_read(&tsg->ch_list_lock);
 
+        if (last_ch)
+                g->ops.fifo.ring_channel_doorbell(last_ch);
+
         return 0;
 }