Commit b28b34ac authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/execlists: Explicitly reset both reg and context runtime 



Upon a GPU reset, we copy the default context image over top of the
guilty image. This will rollback the CTX_TIMESTAMP register to before
our value of ce->runtime.last. Reset both back to 0 so that we do not
encounter an underflow on the next schedule out after resume.

This should not be a huge issue in practice, as hangs should be rare in
correct code.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200330125827.5804-1-chris@chris-wilson.co.uk
parent 0f1dd022

drivers/gpu/drm/i915/gt/intel_lrc.c

+13 −11
Original line number Diff line number Diff line
@@ -238,6 +238,17 @@ __execlists_update_reg_state(const struct intel_context *ce, 
			     const struct intel_engine_cs *engine,

			     u32 head);



static u32 intel_context_get_runtime(const struct intel_context *ce)

{

	/*

	 * We can use either ppHWSP[16] which is recorded before the context

	 * switch (and so excludes the cost of context switches) or use the

	 * value from the context image itself, which is saved/restored earlier

	 * and so includes the cost of the save.

	 */

	return READ_ONCE(ce->lrc_reg_state[CTX_TIMESTAMP]);

}



static void mark_eio(struct i915_request *rq)

{

	if (i915_request_completed(rq))
@@ -1154,6 +1165,7 @@ static void restore_default_state(struct intel_context *ce, 
		       engine->context_size - PAGE_SIZE);



	execlists_init_reg_state(regs, ce, engine, ce->ring, false);

	ce->runtime.last = intel_context_get_runtime(ce);

}



static void reset_active(struct i915_request *rq,
@@ -1195,17 +1207,6 @@ static void reset_active(struct i915_request *rq, 
	ce->lrc_desc |= CTX_DESC_FORCE_RESTORE;

}



static u32 intel_context_get_runtime(const struct intel_context *ce)

{

	/*

	 * We can use either ppHWSP[16] which is recorded before the context

	 * switch (and so excludes the cost of context switches) or use the

	 * value from the context image itself, which is saved/restored earlier

	 * and so includes the cost of the save.

	 */

	return READ_ONCE(ce->lrc_reg_state[CTX_TIMESTAMP]);

}



static void st_update_runtime_underflow(struct intel_context *ce, s32 dt)

{

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
@@ -4614,6 +4615,7 @@ static void init_common_reg_state(u32 * const regs, 
	regs[CTX_CONTEXT_CONTROL] = ctl;



	regs[CTX_RING_CTL] = RING_CTL_SIZE(ring->size) | RING_VALID;

	regs[CTX_TIMESTAMP] = 0;

}



static void init_wa_bb_reg_state(u32 * const regs,

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