[Intel-gfx] [PATCH] drm/i915: Add temporary ring->ctx backpointer

[Daniel Vetter]

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

The execlist patches have a bit a convoluted and long history and due
to that have the actual submission still misplaced deeply burried in
the low-level ringbuffer handling code. This design goes back to the
legacy ringbuffer code with its tricky lazy request and simple work
submissiion using ring tail writes. For that reason they need a
ring->ctx backpointer.

The goal is to unburry that code and move it up into a level where the
full execlist context is available so that we can ditch this
backpointer. Until that's done make it really obvious that there's
work still to be done.

Cc: Oscar Mateo <oscar.mateo at intel.com>
Cc: Thomas Daniel <thomas.daniel at intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

--

Thomas, please ack this patch and the general plan we've discussed.
Then I'll start pulling in more patches and I'll do the
s/ctx/FIXME_lrc_ctx/ on the fly.
-Daniel
---
 drivers/gpu/drm/i915/intel_lrc.c        | 2 ++
 drivers/gpu/drm/i915/intel_ringbuffer.h | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6b5f416b5c0d..c2352d1b23fa 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1086,6 +1086,8 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
 	}
 
 	ringbuf->ring = ring;
+	ringbuf->FIXME_lrc_ctx = ctx;
+
 	ringbuf->size = 32 * PAGE_SIZE;
 	ringbuf->effective_size = ringbuf->size;
 	ringbuf->head = 0;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 24437da91f77..26785ca72530 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -99,6 +99,13 @@ struct intel_ringbuffer {
 
 	struct intel_engine_cs *ring;
 
+	/*
+	 * FIXME: This backpointer is an artifact of the history of how the
+	 * execlist patches came into being. It will get removed once the basic
+	 * code has landed.
+	 */
+	struct intel_context *FIXME_lrc_ctx;
+
 	u32 head;
 	u32 tail;
 	int space;
-- 
2.0.1