drm/i915/guc: drop cached copy of 'wq_head'

Now that we keep the GuC client process descriptor permanently mapped,
we don't really need to keep a local copy of the GuC's work-queue-head.
So we can simplify the code a little by not doing this.

Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index d251699..4718b7a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -238,9 +238,6 @@ static int guc_ring_doorbell(struct i915_guc_client *gc)
                        db_exc.cookie = 1;
        }
 
-       /* Finally, update the cached copy of the GuC's WQ head */
-       gc->wq_head = desc->head;
-
        return ret;
 }
 
@@ -465,17 +462,10 @@ int i915_guc_wq_check_space(struct i915_guc_client *gc)
        if (!gc)
                return 0;
 
-       /* Quickly return if wq space is available since last time we cache the
-        * head position. */
-       if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size)
-               return 0;
-
        desc = gc->client_base + gc->proc_desc_offset;
 
        while (timeout_counter-- > 0) {
-               gc->wq_head = desc->head;
-
-               if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size) {
+               if (CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size) >= size) {
                        ret = 0;
                        break;
                }
@@ -490,11 +480,13 @@ int i915_guc_wq_check_space(struct i915_guc_client *gc)
 static int guc_add_workqueue_item(struct i915_guc_client *gc,
                                  struct drm_i915_gem_request *rq)
 {
+       struct guc_process_desc *desc;
        struct guc_wq_item *wqi;
        void *base;
        u32 tail, wq_len, wq_off, space;
 
-       space = CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size);
+       desc = gc->client_base + gc->proc_desc_offset;
+       space = CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size);
        if (WARN_ON(space < sizeof(struct guc_wq_item)))
                return -ENOSPC; /* shouldn't happen */
 

diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 06050c2..19ca593 100644 (file)
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -46,7 +46,7 @@ struct i915_guc_client {
        uint32_t wq_offset;
        uint32_t wq_size;
        uint32_t wq_tail;
-       uint32_t wq_head;
+       uint32_t unused;                /* Was 'wq_head'                */
 
        /* GuC submission statistics & status */
        uint64_t submissions[GUC_MAX_ENGINES_NUM];