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Commit 167dc10c authored by Kevin Matlage's avatar Kevin Matlage
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msm: kgsl: Briefly turn off interrupts to create a time domain mapping 



This code is attempting to creating a mapping between the GPU time
domain (alwayson counter) and the CPU time domain (local_clock) by
sampling both values as close together as possible. This is useful
for many types of debugging and profiling. In order to make this
mapping as accurate as possible, we must turn off interrupts to
avoid running interrupt handlers between the two samples.

Change-Id: I5a6eb0af93aac44662d29f22006c14ed7ed38c76
Signed-off-by: default avatarKevin Matlage <kmatlage@codeaurora.org>
parent 3511ae2a

drivers/gpu/msm/adreno_ringbuffer.c

+14 −0
Original line number Diff line number Diff line
@@ -83,12 +83,26 @@ void adreno_ringbuffer_submit(struct adreno_ringbuffer *rb, 
	 */



	if (time != NULL) {

		/*

		 * Here we are attempting to create a mapping between the

		 * GPU time domain (alwayson counter) and the CPU time domain

		 * (local_clock) by sampling both values as close together as

		 * possible. This is useful for many types of debugging and

		 * profiling. In order to make this mapping as accurate as

		 * possible, we must turn off interrupts to avoid running

		 * interrupt handlers between the two samples.

		 */

		unsigned long flags;

		local_irq_save(flags);



		if (gpudev->alwayson_counter_read != NULL)

			time->ticks = gpudev->alwayson_counter_read(adreno_dev);

		else

			time->ticks = 0;



		time->clock = local_clock();



		local_irq_restore(flags);

	}



	/* Memory barrier before informing the hardware of new commands */