Commit 58eaa6b3 authored by Vinay Belgaumkar's avatar Vinay Belgaumkar Committed by John Harrison
Browse files

drm/i915/guc/slpc: Use non-blocking H2G for waitboost 



SLPC min/max frequency updates require H2G calls. We are seeing
timeouts when GuC channel is backed up and it is unable to respond
in a timely fashion causing warnings and affecting CI.

This is seen when waitboosting happens during a stress test.
this patch updates the waitboost path to use a non-blocking
H2G call instead, which returns as soon as the message is
successfully transmitted.

v2: Use drm_notice to report any errors that might occur while
sending the waitboost H2G request (Tvrtko)
v3: Add drm_notice inside force_min_freq (Ashutosh)

Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: default avatarVinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: default avatarAshutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220623003225.23301-1-vinay.belgaumkar@intel.com
parent 0667429c

drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c

+35 −7
Original line number Diff line number Diff line
@@ -98,6 +98,30 @@ static u32 slpc_get_state(struct intel_guc_slpc *slpc) 
	return data->header.global_state;

}



static int guc_action_slpc_set_param_nb(struct intel_guc *guc, u8 id, u32 value)

{

	u32 request[] = {

		GUC_ACTION_HOST2GUC_PC_SLPC_REQUEST,

		SLPC_EVENT(SLPC_EVENT_PARAMETER_SET, 2),

		id,

		value,

	};

	int ret;



	ret = intel_guc_send_nb(guc, request, ARRAY_SIZE(request), 0);



	return ret > 0 ? -EPROTO : ret;

}



static int slpc_set_param_nb(struct intel_guc_slpc *slpc, u8 id, u32 value)

{

	struct intel_guc *guc = slpc_to_guc(slpc);



	GEM_BUG_ON(id >= SLPC_MAX_PARAM);



	return guc_action_slpc_set_param_nb(guc, id, value);

}



static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value)

{

	u32 request[] = {
@@ -208,11 +232,13 @@ static int slpc_force_min_freq(struct intel_guc_slpc *slpc, u32 freq) 
	 */



	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {

		ret = slpc_set_param(slpc,

		/* Non-blocking request will avoid stalls */

		ret = slpc_set_param_nb(slpc,

					SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,

					freq);

		if (ret)

			i915_probe_error(i915, "Unable to force min freq to %u: %d",

			drm_notice(&i915->drm,

				   "Failed to send set_param for min freq(%d): (%d)\n",

				   freq, ret);

	}
@@ -222,6 +248,7 @@ static int slpc_force_min_freq(struct intel_guc_slpc *slpc, u32 freq) 
static void slpc_boost_work(struct work_struct *work)

{

	struct intel_guc_slpc *slpc = container_of(work, typeof(*slpc), boost_work);

	int err;



	/*

	 * Raise min freq to boost. It's possible that
@@ -231,7 +258,8 @@ static void slpc_boost_work(struct work_struct *work) 
	 */

	mutex_lock(&slpc->lock);

	if (atomic_read(&slpc->num_waiters)) {

		slpc_force_min_freq(slpc, slpc->boost_freq);

		err = slpc_force_min_freq(slpc, slpc->boost_freq);

		if (!err)

			slpc->num_boosts++;

	}

	mutex_unlock(&slpc->lock);