[PATCH 29/43] drm/i915/bdw: Write the tail pointer, LRC style

Thomas Daniel
2014-07-24T16:05:22Z

From: Oscar Mateo <oscar.mateo@intel.com>

Each logical ring context has the tail pointer in the context object,
so update it before submission.

v2: New namespace.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
---
drivers/gpu/drm/i915/intel_lrc.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 535ef98..5b6f416 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -176,6 +176,21 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
}

+static int execlists_ctx_write_tail(struct drm_i915_gem_object *ctx_obj, u32 tail)
+{
+ struct page *page;
+ uint32_t *reg_state;
+
+ page = i915_gem_object_get_page(ctx_obj, 1);
+ reg_state = kmap_atomic(page);
+
+ reg_state[CTX_RING_TAIL+1] = tail;
+
+ kunmap_atomic(reg_state);
+
+ return 0;
+}
+
static int execlists_submit_context(struct intel_engine_cs *ring,
struct intel_context *to0, u32 tail0,
struct intel_context *to1, u32 tail1)
@@ -187,10 +202,14 @@ static int execlists_submit_context(struct intel_engine_cs *ring,
BUG_ON(!ctx_obj0);
BUG_ON(!i915_gem_obj_is_pinned(ctx_obj0));

+ execlists_ctx_write_tail(ctx_obj0, tail0);
+
if (to1) {
ctx_obj1 = to1->engine[ring->id].state;
BUG_ON(!ctx_obj1);
BUG_ON(!i915_gem_obj_is_pinned(ctx_obj1));
+
+ execlists_ctx_write_tail(ctx_obj1, tail1);
}

execlists_elsp_write(ring, ctx_obj0, ctx_obj1);
--
1.7.9.5