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Commit 517aaffe authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/execlists: Inhibit context save/restore for the fake preempt context 



We only use the preempt context to inject an idle point into execlists.
We never need to reference its logical state, so tell the GPU never to
load it or save it.

v2: BIT(2) for save-inhibit.

N.B. Daniele mentioned this bit mbz for ICL, and has been moved into the
submission process rather than the context image.

Suggested-by: default avatarDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: default avatarMichel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180123210412.17653-1-chris@chris-wilson.co.uk
parent 578f1ac6

drivers/gpu/drm/i915/intel_lrc.c

+4 −0
Original line number Diff line number Diff line
@@ -2237,6 +2237,10 @@ populate_lr_context(struct i915_gem_context *ctx, 
	if (!engine->default_state)

		regs[CTX_CONTEXT_CONTROL + 1] |=

			_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);

	if (ctx->hw_id == PREEMPT_ID)

		regs[CTX_CONTEXT_CONTROL + 1] |=

			_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |

					   CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT);



	i915_gem_object_unpin_map(ctx_obj);

drivers/gpu/drm/i915/intel_lrc.h

+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#define	  CTX_CTRL_INHIBIT_SYN_CTX_SWITCH	(1 << 3)

#define	  CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT	(1 << 0)

#define   CTX_CTRL_RS_CTX_ENABLE                (1 << 1)

#define	  CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT	(1 << 2)

#define RING_CONTEXT_STATUS_BUF_BASE(engine)	_MMIO((engine)->mmio_base + 0x370)

#define RING_CONTEXT_STATUS_BUF_LO(engine, i)	_MMIO((engine)->mmio_base + 0x370 + (i) * 8)

#define RING_CONTEXT_STATUS_BUF_HI(engine, i)	_MMIO((engine)->mmio_base + 0x370 + (i) * 8 + 4)