Commit c20dc369 authored by Christian Koenig's avatar Christian Koenig Committed by Christian König
Browse files

drm/radeon: fix & improve ih ring handling v3 



The spinlock was actually there to protect the
rptr, but rptr was read outside of the locked area.

Also we don't really need a spinlock here, an
atomic should to quite fine since we only need to
prevent it from being reentrant.

v2: Keep the spinlock....
v3: Back to an atomic again after finding & fixing the real bug.

Signed-off-by: default avatarChristian Koenig <christian.koenig@amd.com>
parent 6823d740

drivers/gpu/drm/radeon/evergreen.c

+13 −13
Original line number Diff line number Diff line
@@ -2676,7 +2676,6 @@ int evergreen_irq_process(struct radeon_device *rdev) 
	u32 rptr;

	u32 src_id, src_data;

	u32 ring_index;

	unsigned long flags;

	bool queue_hotplug = false;

	bool queue_hdmi = false;
@@ -2684,22 +2683,21 @@ int evergreen_irq_process(struct radeon_device *rdev) 
		return IRQ_NONE;



	wptr = evergreen_get_ih_wptr(rdev);



restart_ih:

	/* is somebody else already processing irqs? */

	if (atomic_xchg(&rdev->ih.lock, 1))

		return IRQ_NONE;



	rptr = rdev->ih.rptr;

	DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);



	spin_lock_irqsave(&rdev->ih.lock, flags);

	if (rptr == wptr) {

		spin_unlock_irqrestore(&rdev->ih.lock, flags);

		return IRQ_NONE;

	}

restart_ih:

	/* Order reading of wptr vs. reading of IH ring data */

	rmb();



	/* display interrupts */

	evergreen_irq_ack(rdev);



	rdev->ih.wptr = wptr;

	while (rptr != wptr) {

		/* wptr/rptr are in bytes! */

		ring_index = rptr / 4;
@@ -2998,17 +2996,19 @@ restart_ih: 
		rptr += 16;

		rptr &= rdev->ih.ptr_mask;

	}

	/* make sure wptr hasn't changed while processing */

	wptr = evergreen_get_ih_wptr(rdev);

	if (wptr != rdev->ih.wptr)

		goto restart_ih;

	if (queue_hotplug)

		schedule_work(&rdev->hotplug_work);

	if (queue_hdmi)

		schedule_work(&rdev->audio_work);

	rdev->ih.rptr = rptr;

	WREG32(IH_RB_RPTR, rdev->ih.rptr);

	spin_unlock_irqrestore(&rdev->ih.lock, flags);

	atomic_set(&rdev->ih.lock, 0);



	/* make sure wptr hasn't changed while processing */

	wptr = evergreen_get_ih_wptr(rdev);

	if (wptr != rptr)

		goto restart_ih;



	return IRQ_HANDLED;

}

drivers/gpu/drm/radeon/r600.c

+13 −16
Original line number Diff line number Diff line
@@ -2858,7 +2858,6 @@ void r600_disable_interrupts(struct radeon_device *rdev) 
	WREG32(IH_RB_RPTR, 0);

	WREG32(IH_RB_WPTR, 0);

	rdev->ih.enabled = false;

	rdev->ih.wptr = 0;

	rdev->ih.rptr = 0;

}
@@ -3310,7 +3309,6 @@ int r600_irq_process(struct radeon_device *rdev) 
	u32 rptr;

	u32 src_id, src_data;

	u32 ring_index;

	unsigned long flags;

	bool queue_hotplug = false;

	bool queue_hdmi = false;
@@ -3322,24 +3320,21 @@ int r600_irq_process(struct radeon_device *rdev) 
		RREG32(IH_RB_WPTR);



	wptr = r600_get_ih_wptr(rdev);

	rptr = rdev->ih.rptr;

	DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);



	spin_lock_irqsave(&rdev->ih.lock, flags);



	if (rptr == wptr) {

		spin_unlock_irqrestore(&rdev->ih.lock, flags);

restart_ih:

	/* is somebody else already processing irqs? */

	if (atomic_xchg(&rdev->ih.lock, 1))

		return IRQ_NONE;

	}



restart_ih:

	rptr = rdev->ih.rptr;

	DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);



	/* Order reading of wptr vs. reading of IH ring data */

	rmb();



	/* display interrupts */

	r600_irq_ack(rdev);



	rdev->ih.wptr = wptr;

	while (rptr != wptr) {

		/* wptr/rptr are in bytes! */

		ring_index = rptr / 4;
@@ -3493,17 +3488,19 @@ restart_ih: 
		rptr += 16;

		rptr &= rdev->ih.ptr_mask;

	}

	/* make sure wptr hasn't changed while processing */

	wptr = r600_get_ih_wptr(rdev);

	if (wptr != rdev->ih.wptr)

		goto restart_ih;

	if (queue_hotplug)

		schedule_work(&rdev->hotplug_work);

	if (queue_hdmi)

		schedule_work(&rdev->audio_work);

	rdev->ih.rptr = rptr;

	WREG32(IH_RB_RPTR, rdev->ih.rptr);

	spin_unlock_irqrestore(&rdev->ih.lock, flags);

	atomic_set(&rdev->ih.lock, 0);



	/* make sure wptr hasn't changed while processing */

	wptr = r600_get_ih_wptr(rdev);

	if (wptr != rptr)

		goto restart_ih;



	return IRQ_HANDLED;

}

drivers/gpu/drm/radeon/radeon.h

+1 −2
Original line number Diff line number Diff line
@@ -738,11 +738,10 @@ struct r600_ih { 
	struct radeon_bo	*ring_obj;

	volatile uint32_t	*ring;

	unsigned		rptr;

	unsigned		wptr;

	unsigned		ring_size;

	uint64_t		gpu_addr;

	uint32_t		ptr_mask;

	spinlock_t              lock;

	atomic_t		lock;

	bool                    enabled;

};

drivers/gpu/drm/radeon/radeon_device.c

+1 −2
Original line number Diff line number Diff line
@@ -731,8 +731,7 @@ int radeon_device_init(struct radeon_device *rdev, 
	radeon_mutex_init(&rdev->cs_mutex);

	mutex_init(&rdev->ring_lock);

	mutex_init(&rdev->dc_hw_i2c_mutex);

	if (rdev->family >= CHIP_R600)

		spin_lock_init(&rdev->ih.lock);

	atomic_set(&rdev->ih.lock, 0);

	mutex_init(&rdev->gem.mutex);

	mutex_init(&rdev->pm.mutex);

	init_rwsem(&rdev->pm.mclk_lock);

drivers/gpu/drm/radeon/si.c

+13 −14
Original line number Diff line number Diff line
@@ -2942,7 +2942,6 @@ static void si_disable_interrupts(struct radeon_device *rdev) 
	WREG32(IH_RB_RPTR, 0);

	WREG32(IH_RB_WPTR, 0);

	rdev->ih.enabled = false;

	rdev->ih.wptr = 0;

	rdev->ih.rptr = 0;

}
@@ -3359,29 +3358,27 @@ int si_irq_process(struct radeon_device *rdev) 
	u32 rptr;

	u32 src_id, src_data, ring_id;

	u32 ring_index;

	unsigned long flags;

	bool queue_hotplug = false;



	if (!rdev->ih.enabled || rdev->shutdown)

		return IRQ_NONE;



	wptr = si_get_ih_wptr(rdev);



restart_ih:

	/* is somebody else already processing irqs? */

	if (atomic_xchg(&rdev->ih.lock, 1))

		return IRQ_NONE;



	rptr = rdev->ih.rptr;

	DRM_DEBUG("si_irq_process start: rptr %d, wptr %d\n", rptr, wptr);



	spin_lock_irqsave(&rdev->ih.lock, flags);

	if (rptr == wptr) {

		spin_unlock_irqrestore(&rdev->ih.lock, flags);

		return IRQ_NONE;

	}

restart_ih:

	/* Order reading of wptr vs. reading of IH ring data */

	rmb();



	/* display interrupts */

	si_irq_ack(rdev);



	rdev->ih.wptr = wptr;

	while (rptr != wptr) {

		/* wptr/rptr are in bytes! */

		ring_index = rptr / 4;
@@ -3632,15 +3629,17 @@ restart_ih: 
		rptr += 16;

		rptr &= rdev->ih.ptr_mask;

	}

	/* make sure wptr hasn't changed while processing */

	wptr = si_get_ih_wptr(rdev);

	if (wptr != rdev->ih.wptr)

		goto restart_ih;

	if (queue_hotplug)

		schedule_work(&rdev->hotplug_work);

	rdev->ih.rptr = rptr;

	WREG32(IH_RB_RPTR, rdev->ih.rptr);

	spin_unlock_irqrestore(&rdev->ih.lock, flags);

	atomic_set(&rdev->ih.lock, 0);



	/* make sure wptr hasn't changed while processing */

	wptr = si_get_ih_wptr(rdev);

	if (wptr != rptr)

		goto restart_ih;



	return IRQ_HANDLED;

}

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