From: Michał Winiarski <michal.winiarski@xxxxxxxxx> All we're really doing is incrementing a simple counter in a doorbell_info struct. We can do without extra variables and a separate counter kept in guc_client. Since it's gone, we're also removing its debugfs. The only functional change here, is that we're no longer treating 0 as a special value. GuC doesn't seem to care, why should we? v2: Restore desc->tail update. v3: Drop the retry loop, assert that doorbell cookie doesn't change behind our back. v4: WARN rather than BUG, use xchg. (Chris) Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx> Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx> Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20170914105125.3031-1-michal.winiarski@xxxxxxxxx Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_debugfs.c | 4 +- drivers/gpu/drm/i915/i915_guc_submission.c | 60 +++++++----------------------- drivers/gpu/drm/i915/intel_uc.h | 1 - 3 files changed, 15 insertions(+), 50 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 0364f0d2d76e..57821dcd2001 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -2446,8 +2446,8 @@ static void i915_guc_client_info(struct seq_file *m, seq_printf(m, "\tPriority %d, GuC stage index: %u, PD offset 0x%x\n", client->priority, client->stage_id, client->proc_desc_offset); - seq_printf(m, "\tDoorbell id %d, offset: 0x%lx, cookie 0x%x\n", - client->doorbell_id, client->doorbell_offset, client->doorbell_cookie); + seq_printf(m, "\tDoorbell id %d, offset: 0x%lx\n", + client->doorbell_id, client->doorbell_offset); seq_printf(m, "\tWQ size %d, offset: 0x%x, tail %d\n", client->wq_size, client->wq_offset, client->wq_tail); diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index 16b31f70114e..065832413a26 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -192,13 +192,12 @@ static int __create_doorbell(struct i915_guc_client *client) doorbell = __get_doorbell(client); doorbell->db_status = GUC_DOORBELL_ENABLED; - doorbell->cookie = client->doorbell_cookie; + doorbell->cookie = 0; err = __guc_allocate_doorbell(client->guc, client->stage_id); - if (err) { + if (err) doorbell->db_status = GUC_DOORBELL_DISABLED; - doorbell->cookie = 0; - } + return err; } @@ -466,57 +465,24 @@ static void guc_reset_wq(struct i915_guc_client *client) client->wq_tail = 0; } -static int guc_ring_doorbell(struct i915_guc_client *client) +static void guc_ring_doorbell(struct i915_guc_client *client) { struct guc_process_desc *desc = __get_process_desc(client); - union guc_doorbell_qw db_cmp, db_exc, db_ret; - union guc_doorbell_qw *db; - int attempt = 2, ret = -EAGAIN; + struct guc_doorbell_info *db; + u32 cookie; /* Update the tail so it is visible to GuC */ desc->tail = client->wq_tail; - /* current cookie */ - db_cmp.db_status = GUC_DOORBELL_ENABLED; - db_cmp.cookie = client->doorbell_cookie; - - /* cookie to be updated */ - db_exc.db_status = GUC_DOORBELL_ENABLED; - db_exc.cookie = client->doorbell_cookie + 1; - if (db_exc.cookie == 0) - db_exc.cookie = 1; - /* pointer of current doorbell cacheline */ - db = (union guc_doorbell_qw *)__get_doorbell(client); - - while (attempt--) { - /* lets ring the doorbell */ - db_ret.value_qw = atomic64_cmpxchg((atomic64_t *)db, - db_cmp.value_qw, db_exc.value_qw); - - /* if the exchange was successfully executed */ - if (db_ret.value_qw == db_cmp.value_qw) { - /* db was successfully rung */ - client->doorbell_cookie = db_exc.cookie; - ret = 0; - break; - } - - /* XXX: doorbell was lost and need to acquire it again */ - if (db_ret.db_status == GUC_DOORBELL_DISABLED) - break; + db = __get_doorbell(client); - DRM_WARN("Cookie mismatch. Expected %d, found %d\n", - db_cmp.cookie, db_ret.cookie); + /* we're not expecting the doorbell cookie to change behind our back */ + cookie = READ_ONCE(db->cookie); + WARN_ON_ONCE(xchg(&db->cookie, cookie + 1) != cookie); - /* update the cookie to newly read cookie from GuC */ - db_cmp.cookie = db_ret.cookie; - db_exc.cookie = db_ret.cookie + 1; - if (db_exc.cookie == 0) - db_exc.cookie = 1; - } - - return ret; + /* XXX: doorbell was lost and need to acquire it again */ + GEM_BUG_ON(db->db_status != GUC_DOORBELL_ENABLED); } /** @@ -550,7 +516,7 @@ static void i915_guc_submit(struct intel_engine_cs *engine) spin_lock_irqsave(&client->wq_lock, flags); guc_wq_item_append(client, rq); - WARN_ON(guc_ring_doorbell(client)); + guc_ring_doorbell(client); client->submissions[engine_id] += 1; diff --git a/drivers/gpu/drm/i915/intel_uc.h b/drivers/gpu/drm/i915/intel_uc.h index d41051688221..f505dcccd613 100644 --- a/drivers/gpu/drm/i915/intel_uc.h +++ b/drivers/gpu/drm/i915/intel_uc.h @@ -66,7 +66,6 @@ struct i915_guc_client { u16 doorbell_id; unsigned long doorbell_offset; - u32 doorbell_cookie; spinlock_t wq_lock; uint32_t wq_offset; -- 2.14.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
