gpu: nvgpu: Fix timeout error in suspend_contexts

* Moving jiffy counter after preemption work to more accurately and fairly give
time for preemption to complete.
* Add debug information to coordinate waiting.
* Check if cilp is still pending before returning the timedout error.

Bug 1700310

Change-Id: Ic16bb3b11f2cd5aea9a5a85b5e0d9927732a065c
Signed-off-by: Cory Perry <cperry@nvidia.com>
Reviewed-on: http://git-master/r/1151907
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
index 86cc0555..205d2c97 100644
--- a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
+++ b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
@@ -1953,8 +1953,6 @@ static int gr_gp10b_suspend_contexts(struct gk20a *g,
                                 struct dbg_session_gk20a *dbg_s,
                                 int *ctx_resident_ch_fd)
 {
-        unsigned long end_jiffies = jiffies +
-                msecs_to_jiffies(gk20a_get_gr_idle_timeout(g));
         u32 delay = GR_IDLE_CHECK_DEFAULT;
         bool cilp_preempt_pending = false;
         struct channel_gk20a *cilp_preempt_pending_ch = NULL;
@@ -2000,6 +1998,12 @@ static int gr_gp10b_suspend_contexts(struct gk20a *g,
                 struct channel_ctx_gk20a *ch_ctx =
                                 &cilp_preempt_pending_ch->ch_ctx;
                 struct gr_ctx_desc *gr_ctx = ch_ctx->gr_ctx;
+                unsigned long end_jiffies = jiffies +
+                        msecs_to_jiffies(gk20a_get_gr_idle_timeout(g));
+
+                gk20a_dbg(gpu_dbg_fn | gpu_dbg_gpu_dbg | gpu_dbg_intr,
+                        "CILP preempt pending, waiting %lu msecs for preemption",
+                        gk20a_get_gr_idle_timeout(g));
 
                 do {
                         if (!gr_ctx->t18x.cilp_preempt_pending)
@@ -2010,7 +2014,9 @@ static int gr_gp10b_suspend_contexts(struct gk20a *g,
                 } while (time_before(jiffies, end_jiffies)
                         || !tegra_platform_is_silicon());
 
-                err = -ETIMEDOUT;
+                /* If cilp is still pending at this point, timeout */
+                if (gr_ctx->t18x.cilp_preempt_pending)
+                        err = -ETIMEDOUT;
         }
 
         *ctx_resident_ch_fd = local_ctx_resident_ch_fd;