gpu: nvgpu: check ctx valid bit at right place

When contexts are unloaded from GR, the valid bit is reset
but the instance pointer information remains intact.
Check valid bit in *is_channel_ctx_resident* function as
valid bit might not be set when *get_channel_from_ctx function*
is called from gr_isr

Bug 200289491

Change-Id: I4da7f04794c7e7e80b511756dbd851205cd76fbc
Signed-off-by: Seema Khowala <seemaj@nvidia.com>
Reviewed-on: http://git-master/r/1505908
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index 4219e841..2afa79f1 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -5906,11 +5906,10 @@ static struct channel_gk20a *gk20a_gr_get_channel_from_ctx(
         struct channel_gk20a *ret = NULL;
 
         /* when contexts are unloaded from GR, the valid bit is reset
-         * but the instance pointer information remains intact. So the
-         * valid bit must be checked to be absolutely certain that a
-         * valid context is currently resident. */
-        if (!gr_fecs_current_ctx_valid_v(curr_ctx))
-                return NULL;
+         * but the instance pointer information remains intact.
+         * This might be called from gr_isr where contexts might be
+         * unloaded. No need to check ctx_valid bit
+         */
 
         nvgpu_spinlock_acquire(&gr->ch_tlb_lock);
 
@@ -6475,10 +6474,12 @@ int gk20a_gr_isr(struct gk20a *g)
         isr_data.class_num = gr_fe_object_table_nvclass_v(obj_table);
 
         ch = gk20a_gr_get_channel_from_ctx(g, isr_data.curr_ctx, &tsgid);
-        if (ch)
+        if (ch) {
                 isr_data.chid = ch->hw_chid;
-        else
+        } else {
                 isr_data.chid = FIFO_INVAL_CHANNEL_ID;
+                nvgpu_err(g, "ch id is INVALID 0xffffffff");
+        }
 
         gk20a_dbg(gpu_dbg_intr | gpu_dbg_gpu_dbg,
                 "channel %d: addr 0x%08x, "
@@ -8283,6 +8284,15 @@ bool gk20a_is_channel_ctx_resident(struct channel_gk20a *ch)
         bool ret = false;
 
         curr_gr_ctx  = gk20a_readl(g, gr_fecs_current_ctx_r());
+
+        /* when contexts are unloaded from GR, the valid bit is reset
+         * but the instance pointer information remains intact. So the
+         * valid bit must be checked to be absolutely certain that a
+         * valid context is currently resident.
+         */
+        if (!gr_fecs_current_ctx_valid_v(curr_gr_ctx))
+                return NULL;
+
         curr_ch = gk20a_gr_get_channel_from_ctx(g, curr_gr_ctx,
                                               &curr_gr_tsgid);