[PATCH v3] drm/amdkfd: Fix bug in config_dequeue_wait_counts

[Harish Kasiviswanathan]

For certain ASICs where dequeue_wait_count don't need to be initialized,
pm_config_dequeue_wait_counts_v9 return without filling in the packet
information. However, the calling function interprets this as a success
and sends the uninitialized packet to firmware causing hang.

Fix the above bug by not calling pm_config_dequeue_wait_counts_v9 for
ASICs that don't need the value to be initialized.

v2: Removed redudant code.
    Tidy up code based on review comments
v3: Don't call pm_config_dequeue_wait_counts_v9 for certain ASICs

Fixes: <98a5af8103f> ("drm/amdkfd: Add pm_config_dequeue_wait_counts API")

Signed-off-by: Harish Kasiviswanathan <harish.kasiviswanat...@amd.com>
---
 .../gpu/drm/amd/amdkfd/kfd_packet_manager.c   | 16 ++++++----
 .../drm/amd/amdkfd/kfd_packet_manager_v9.c    | 30 +++++++++++--------
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
index 3f574d82b5fc..8a47b7259a10 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
@@ -418,6 +418,10 @@ int pm_config_dequeue_wait_counts(struct packet_manager 
*pm,
            !pm->pmf->config_dequeue_wait_counts_size)
                return 0;
 
+       if (cmd == KFD_DEQUEUE_WAIT_INIT && (KFD_GC_VERSION(pm->dqm->dev) < 
IP_VERSION(9, 4, 1) ||
+          KFD_GC_VERSION(pm->dqm->dev) >= IP_VERSION(10, 0, 0)))
+               return 0;
+
        size = pm->pmf->config_dequeue_wait_counts_size;
 
        mutex_lock(&pm->lock);
@@ -436,16 +440,16 @@ int pm_config_dequeue_wait_counts(struct packet_manager 
*pm,
 
                retval = pm->pmf->config_dequeue_wait_counts(pm, buffer,
                                                             cmd, value);
-               if (!retval)
+               if (!retval) {
                        retval = kq_submit_packet(pm->priv_queue);
+
+                       /* If default value is modified, cache that in 
dqm->wait_times */
+                       if (!retval && cmd == KFD_DEQUEUE_WAIT_INIT)
+                               update_dqm_wait_times(pm->dqm);
+               }
                else
                        kq_rollback_packet(pm->priv_queue);
        }
-
-       /* If default value is modified, cache that value in dqm->wait_times */
-       if (!retval && cmd == KFD_DEQUEUE_WAIT_INIT)
-               update_dqm_wait_times(pm->dqm);
-
 out:
        mutex_unlock(&pm->lock);
        return retval;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
index d440df602393..f059041902bc 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
@@ -310,6 +310,13 @@ static inline void 
pm_build_dequeue_wait_counts_packet_info(struct packet_manage
                reg_data);
 }
 
+/* pm_config_dequeue_wait_counts_v9: Builds WRITE_DATA packet with
+ *    register/value for configuring dequeue wait counts
+ *
+ * @return: -ve for failure and 0 for success and buffer is
+ *  filled in with packet
+ *
+ **/
 static int pm_config_dequeue_wait_counts_v9(struct packet_manager *pm,
                uint32_t *buffer,
                enum kfd_config_dequeue_wait_counts_cmd cmd,
@@ -321,24 +328,21 @@ static int pm_config_dequeue_wait_counts_v9(struct 
packet_manager *pm,
 
        switch (cmd) {
        case KFD_DEQUEUE_WAIT_INIT: {
-               uint32_t sch_wave = 0, que_sleep = 0;
-               /* Reduce CP_IQ_WAIT_TIME2.QUE_SLEEP to 0x1 from default 0x40.
+               uint32_t sch_wave = 0, que_sleep = 1;
+
+               /* For all gfx9 ASICs > gfx941,
+                * Reduce CP_IQ_WAIT_TIME2.QUE_SLEEP to 0x1 from default 0x40.
                 * On a 1GHz machine this is roughly 1 microsecond, which is
                 * about how long it takes to load data out of memory during
                 * queue connect
                 * QUE_SLEEP: Wait Count for Dequeue Retry.
+                *
+                * Set CWSR grace period to 1x1000 cycle for GFX9.4.3 APU
                 */
-               if (KFD_GC_VERSION(pm->dqm->dev) >= IP_VERSION(9, 4, 1) &&
-                   KFD_GC_VERSION(pm->dqm->dev) < IP_VERSION(10, 0, 0)) {
-                       que_sleep = 1;
-
-                       /* Set CWSR grace period to 1x1000 cycle for GFX9.4.3 
APU */
-                       if (amdgpu_emu_mode == 0 && 
pm->dqm->dev->adev->gmc.is_app_apu &&
-                       (KFD_GC_VERSION(pm->dqm->dev) == IP_VERSION(9, 4, 3)))
-                               sch_wave = 1;
-               } else {
-                       return 0;
-               }
+               if (amdgpu_emu_mode == 0 && pm->dqm->dev->adev->gmc.is_app_apu 
&&
+                   (KFD_GC_VERSION(pm->dqm->dev) == IP_VERSION(9, 4, 3)))
+                       sch_wave = 1;
+
                pm_build_dequeue_wait_counts_packet_info(pm, sch_wave, 
que_sleep,
                        &reg_offset, &reg_data);
 
-- 
2.34.1