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Commit 764725a6 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Sasha Levin
Browse files

drm/radeon: fix wait to actually occur after the signaling callback 

[ Upstream commit b6610101718d4ab90d793c482625e98eb1262cad ]

A normal wait adds to the front of the tail. By doing something
similar to fence_default_wait the fence code can run without racing.

This is a complete fix for "panic on suspend from KDE with radeon",
and a partial fix for "Radeon: System pauses on TAHITI". On tahiti
si_irq_set needs to be fixed too, to completely flush the writes
before radeon_fence_activity is called in radeon_fence_enable_signaling.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=90741
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=90861


Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@ubuntu.com>
Reported-by: default avatarJon Arne Jørgensen <jonjon.arnearne@gmail.com>
Reported-and-tested-by: default avatarGustaw Smolarczyk <wielkiegie@gmail.com>
Cc: stable@vger.kernel.org (v3.18+)
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 6eef27b6

drivers/gpu/drm/radeon/radeon_fence.c

+45 −23
Original line number Diff line number Diff line
@@ -1029,37 +1029,59 @@ static inline bool radeon_test_signaled(struct radeon_fence *fence) 
	return test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);

}



struct radeon_wait_cb {

	struct fence_cb base;

	struct task_struct *task;

};



static void

radeon_fence_wait_cb(struct fence *fence, struct fence_cb *cb)

{

	struct radeon_wait_cb *wait =

		container_of(cb, struct radeon_wait_cb, base);



	wake_up_process(wait->task);

}



static signed long radeon_fence_default_wait(struct fence *f, bool intr,

					     signed long t)

{

	struct radeon_fence *fence = to_radeon_fence(f);

	struct radeon_device *rdev = fence->rdev;

	bool signaled;

	struct radeon_wait_cb cb;



	fence_enable_sw_signaling(&fence->base);

	cb.task = current;



	/*

	 * This function has to return -EDEADLK, but cannot hold

	 * exclusive_lock during the wait because some callers

	 * may already hold it. This means checking needs_reset without

	 * lock, and not fiddling with any gpu internals.

	 *

	 * The callback installed with fence_enable_sw_signaling will

	 * run before our wait_event_*timeout call, so we will see

	 * both the signaled fence and the changes to needs_reset.

	 */

	if (fence_add_callback(f, &cb.base, radeon_fence_wait_cb))

		return t;



	while (t > 0) {

		if (intr)

		t = wait_event_interruptible_timeout(rdev->fence_queue,

			((signaled = radeon_test_signaled(fence)) ||

			 rdev->needs_reset), t);

			set_current_state(TASK_INTERRUPTIBLE);

		else

		t = wait_event_timeout(rdev->fence_queue,

			((signaled = radeon_test_signaled(fence)) ||

			 rdev->needs_reset), t);

			set_current_state(TASK_UNINTERRUPTIBLE);



		/*

		 * radeon_test_signaled must be called after

		 * set_current_state to prevent a race with wake_up_process

		 */

		if (radeon_test_signaled(fence))

			break;



		if (rdev->needs_reset) {

			t = -EDEADLK;

			break;

		}



		t = schedule_timeout(t);



		if (t > 0 && intr && signal_pending(current))

			t = -ERESTARTSYS;

	}



	__set_current_state(TASK_RUNNING);

	fence_remove_callback(f, &cb.base);



	if (t > 0 && !signaled)

		return -EDEADLK;

	return t;

}