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Commit c3c3b9b5 authored by Lucille Sylvester's avatar Lucille Sylvester
Browse files

msm: kgsl: Remove the busy waiting loop from idle_check 



Previously there were issues with extra long GPU sequences
running during the idle_check NAP attempt thwarting the
transition to NAP.  With the dispatcher architecture this
is much less likely to occur.  In addition the dispatcher
increases chances of a very short pause between a command
coming in and being submitted increasing the occurence of
"micro-NAPs" being caught by this loop.  These extremely
short NAP periods are actually a power loss on the CX rail.
Given that hw clock gating will take care of any long GPU
command tails remove the busy wait loop for power savings.

Change-Id: I4efc6215689c42ab03d4e478ad97839208d04004
Signed-off-by: default avatarLucille Sylvester <lsylvest@codeaurora.org>
parent a888b526

drivers/gpu/msm/adreno_a3xx.c

+0 −1
Original line number Diff line number Diff line
@@ -863,7 +863,6 @@ void a3xx_cp_callback(struct adreno_device *adreno_dev, int irq) 
{

	struct kgsl_device *device = &adreno_dev->dev;



	device->pwrctrl.irq_last = 1;

	queue_work(device->work_queue, &device->event_work);

	adreno_dispatcher_schedule(device);

}

drivers/gpu/msm/adreno_ringbuffer.c

+0 −1
Original line number Diff line number Diff line
@@ -1288,7 +1288,6 @@ int adreno_ringbuffer_submitcmd(struct adreno_device *adreno_dev, 
	kgsl_cff_core_idle(device);



done:

	device->pwrctrl.irq_last = 0;

	trace_kgsl_issueibcmds(device, context->id, cmdbatch,

		cmdbatch->timestamp, cmdbatch->flags, ret,

		drawctxt->type);

drivers/gpu/msm/kgsl_pwrctrl.c

+2 −27
Original line number Diff line number Diff line
@@ -1195,8 +1195,6 @@ void kgsl_pwrctrl_close(struct kgsl_device *device) 
 */

void kgsl_idle_check(struct work_struct *work)

{

	int delay = INIT_UDELAY;

	int requested_state;

	struct kgsl_device *device = container_of(work, struct kgsl_device,

							idle_check_ws);

	WARN_ON(device == NULL);
@@ -1209,30 +1207,9 @@ void kgsl_idle_check(struct work_struct *work) 


	if (device->state == KGSL_STATE_ACTIVE

		   || device->state ==  KGSL_STATE_NAP) {

		/*

		 * If no user is explicitly trying to use the GPU

		 * (active_cnt is zero), then loop with increasing delay,

		 * waiting for the GPU to become idle.

		 */

		while (!atomic_read(&device->active_cnt) &&

			(delay < MAX_UDELAY)) {

			requested_state = device->requested_state;

			if (!kgsl_pwrctrl_sleep(device))

				break;

			/*

			 * If no new commands have been issued since the

			 * last interrupt, stay in this loop waiting for

			 * the GPU to become idle.

			 */

			if (!device->pwrctrl.irq_last)

				break;

			kgsl_pwrctrl_request_state(device, requested_state);

			mutex_unlock(&device->mutex);

			udelay(delay);

			delay *= 2;

			mutex_lock(&device->mutex);

		}



		if (!atomic_read(&device->active_cnt))

			kgsl_pwrctrl_sleep(device);



		kgsl_pwrctrl_request_state(device, KGSL_STATE_NONE);

		if (device->state == KGSL_STATE_ACTIVE) {
@@ -1249,8 +1226,6 @@ void kgsl_idle_check(struct work_struct *work) 
				kgsl_pwrctrl_busy_time(device, true);

				device->pwrctrl.clk_stats.no_nap_cnt = 0;

			}

		} else {

			device->pwrctrl.irq_last = 0;

		}

	}

drivers/gpu/msm/kgsl_pwrctrl.h

+0 −1
Original line number Diff line number Diff line
@@ -106,7 +106,6 @@ struct kgsl_pwrctrl { 
	struct kgsl_clk_stats clk_stats;

	struct pm_qos_request pm_qos_req_dma;

	unsigned int pm_qos_latency;

	unsigned int irq_last;

	bool bus_control;

	int bus_mod;

	unsigned int bus_index[KGSL_MAX_PWRLEVELS];