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Commit 0afacebf authored by Suman Tatiraju's avatar Suman Tatiraju
Browse files

msm: kgsl: Fix race condition in adreno_spin_idle() 



adreno_spin_idle spins for a timeout checking for gpu to idle.
Sometimes due to race conditions the timeout can occur before the
loop is executed. Change the logic to a do-while loop and add an
extra idle check after the timeout before returning failure.

CRs-Fixed: 978122
Change-Id: Idb92a0180dd8cc3e662b1ccf44d69e4bbafb29f1
Signed-off-by: default avatarSuman Tatiraju <sumant@codeaurora.org>
parent 1c10389d

drivers/gpu/msm/adreno.c

+14 −2
Original line number Original line Diff line number Diff line
@@ -2142,7 +2142,7 @@ int adreno_spin_idle(struct adreno_device *adreno_dev, unsigned int timeout) 
		adreno_getreg(adreno_dev, ADRENO_REG_RBBM_STATUS) << 2,

		adreno_getreg(adreno_dev, ADRENO_REG_RBBM_STATUS) << 2,

		0x00000000, 0x80000000);

		0x00000000, 0x80000000);





	while (time_before(jiffies, wait)) {

	do {

		/*

		/*

		 * If we fault, stop waiting and return an error. The dispatcher

		 * If we fault, stop waiting and return an error. The dispatcher

		 * will clean up the fault from the work queue, but we need to

		 * will clean up the fault from the work queue, but we need to
@@ -2155,7 +2155,19 @@ int adreno_spin_idle(struct adreno_device *adreno_dev, unsigned int timeout) 




		if (adreno_isidle(KGSL_DEVICE(adreno_dev)))

		if (adreno_isidle(KGSL_DEVICE(adreno_dev)))

			return 0;

			return 0;

	}



	} while (time_before(jiffies, wait));



	/*

	 * Under rare conditions, preemption can cause the while loop to exit

	 * without checking if the gpu is idle. check one last time before we

	 * return failure.

	 */

	if (adreno_gpu_fault(adreno_dev) != 0)

		return -EDEADLK;



	if (adreno_isidle(KGSL_DEVICE(adreno_dev)))

		return 0;





	return -ETIMEDOUT;

	return -ETIMEDOUT;

}

}