Commit ef87bba8 authored by Chris Wilson's avatar Chris Wilson

drm/i915: Update execlists context descriptor format commentary

The comments describing the Context Descriptor Format are off by a bit
for the size of the context ID.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-16-git-send-email-chris@chris-wilson.co.uk
parent 6310346e
...@@ -305,10 +305,11 @@ logical_ring_init_platform_invariants(struct intel_engine_cs *engine) ...@@ -305,10 +305,11 @@ logical_ring_init_platform_invariants(struct intel_engine_cs *engine)
* which remains valid until the context is unpinned. * which remains valid until the context is unpinned.
* *
* This is what a descriptor looks like, from LSB to MSB: * This is what a descriptor looks like, from LSB to MSB:
* bits 0-11: flags, GEN8_CTX_* (cached in ctx_desc_template) * bits 0-11: flags, GEN8_CTX_* (cached in ctx_desc_template)
* bits 12-31: LRCA, GTT address of (the HWSP of) this context * bits 12-31: LRCA, GTT address of (the HWSP of) this context
* bits 32-51: ctx ID, a globally unique tag (the LRCA again!) * bits 32-52: ctx ID, a globally unique tag (the LRCA again!)
* bits 52-63: reserved, may encode the engine ID (for GuC) * bits 53-54: mbz, reserved for use by hardware
* bits 55-63: group ID, currently unused and set to 0
*/ */
static void static void
intel_lr_context_descriptor_update(struct intel_context *ctx, intel_lr_context_descriptor_update(struct intel_context *ctx,
...@@ -319,9 +320,9 @@ intel_lr_context_descriptor_update(struct intel_context *ctx, ...@@ -319,9 +320,9 @@ intel_lr_context_descriptor_update(struct intel_context *ctx,
lrca = ctx->engine[engine->id].lrc_vma->node.start + lrca = ctx->engine[engine->id].lrc_vma->node.start +
LRC_PPHWSP_PN * PAGE_SIZE; LRC_PPHWSP_PN * PAGE_SIZE;
desc = engine->ctx_desc_template; /* bits 0-11 */ desc = engine->ctx_desc_template; /* bits 0-11 */
desc |= lrca; /* bits 12-31 */ desc |= lrca; /* bits 12-31 */
desc |= (lrca >> PAGE_SHIFT) << GEN8_CTX_ID_SHIFT; /* bits 32-51 */ desc |= (lrca >> PAGE_SHIFT) << GEN8_CTX_ID_SHIFT; /* bits 32-52 */
ctx->engine[engine->id].lrc_desc = desc; ctx->engine[engine->id].lrc_desc = desc;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment