From 73e4d07f8ae9cff8c869d73df4e299a3a6f5ad98 Mon Sep 17 00:00:00 2001 From: Oscar Mateo Date: Thu, 24 Jul 2014 17:04:48 +0100 Subject: drm/i915/bdw: Document Logical Rings, LR contexts and Execlists Add theory of operation notes to intel_lrc.c and comments to externally visible functions. v2: Add notes on logical ring context creation. v3: Use kerneldoc. v4: Integrate it in the DocBook template. Signed-off-by: Thomas Daniel (v1) Signed-off-by: Oscar Mateo (v2, v3) Reviewed-by: Damien Lespiau [danvet: Drop hunk about render ring init function since that's not yet merged.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_lrc.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_lrc.h') diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h index 117d1a4eb3b9..991d4499fb03 100644 --- a/drivers/gpu/drm/i915/intel_lrc.h +++ b/drivers/gpu/drm/i915/intel_lrc.h @@ -38,10 +38,21 @@ int intel_logical_rings_init(struct drm_device *dev); int logical_ring_flush_all_caches(struct intel_ringbuffer *ringbuf); void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf); +/** + * intel_logical_ring_advance() - advance the ringbuffer tail + * @ringbuf: Ringbuffer to advance. + * + * The tail is only updated in our logical ringbuffer struct. + */ static inline void intel_logical_ring_advance(struct intel_ringbuffer *ringbuf) { ringbuf->tail &= ringbuf->size - 1; } +/** + * intel_logical_ring_emit() - write a DWORD to the ringbuffer. + * @ringbuf: Ringbuffer to write to. + * @data: DWORD to write. + */ static inline void intel_logical_ring_emit(struct intel_ringbuffer *ringbuf, u32 data) { @@ -66,6 +77,25 @@ int intel_execlists_submission(struct drm_device *dev, struct drm_file *file, u64 exec_start, u32 flags); u32 intel_execlists_ctx_id(struct drm_i915_gem_object *ctx_obj); +/** + * struct intel_ctx_submit_request - queued context submission request + * @ctx: Context to submit to the ELSP. + * @ring: Engine to submit it to. + * @tail: how far in the context's ringbuffer this request goes to. + * @execlist_link: link in the submission queue. + * @work: workqueue for processing this request in a bottom half. + * @elsp_submitted: no. of times this request has been sent to the ELSP. + * + * The ELSP only accepts two elements at a time, so we queue context/tail + * pairs on a given queue (ring->execlist_queue) until the hardware is + * available. The queue serves a double purpose: we also use it to keep track + * of the up to 2 contexts currently in the hardware (usually one in execution + * and the other queued up by the GPU): We only remove elements from the head + * of the queue when the hardware informs us that an element has been + * completed. + * + * All accesses to the queue are mediated by a spinlock (ring->execlist_lock). + */ struct intel_ctx_submit_request { struct intel_context *ctx; struct intel_engine_cs *ring; -- cgit