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Commit 1ed134e6 authored by Boris Brezillon's avatar Boris Brezillon Committed by Eric Anholt
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drm/vc4: Fix VBLANK handling in crtc->enable() path 



When we are enabling a CRTC, drm_crtc_vblank_get() is called before
drm_crtc_vblank_on(), which is not supposed to happen (hence the
WARN_ON() in the code). To solve the problem, we delay the 'update
display list' operation after the CRTC is actually enabled.

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/1498163126-26678-1-git-send-email-boris.brezillon@free-electrons.com
Fixes: 34c8ea40 ("drm/vc4: Mimic drm_atomic_helper_commit() behavior")
parent 6f6e0b21

drivers/gpu/drm/vc4/vc4_crtc.c

+43 −23
Original line number Diff line number Diff line
@@ -520,6 +520,34 @@ static void vc4_crtc_disable(struct drm_crtc *crtc) 
		     SCALER_DISPSTATX_EMPTY);

}



static void vc4_crtc_update_dlist(struct drm_crtc *crtc)

{

	struct drm_device *dev = crtc->dev;

	struct vc4_dev *vc4 = to_vc4_dev(dev);

	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);

	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);



	if (crtc->state->event) {

		unsigned long flags;



		crtc->state->event->pipe = drm_crtc_index(crtc);



		WARN_ON(drm_crtc_vblank_get(crtc) != 0);



		spin_lock_irqsave(&dev->event_lock, flags);

		vc4_crtc->event = crtc->state->event;

		crtc->state->event = NULL;



		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),

			  vc4_state->mm.start);



		spin_unlock_irqrestore(&dev->event_lock, flags);

	} else {

		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),

			  vc4_state->mm.start);

	}

}



static void vc4_crtc_enable(struct drm_crtc *crtc)

{

	struct drm_device *dev = crtc->dev;
@@ -530,6 +558,12 @@ static void vc4_crtc_enable(struct drm_crtc *crtc) 


	require_hvs_enabled(dev);



	/* Enable vblank irq handling before crtc is started otherwise

	 * drm_crtc_get_vblank() fails in vc4_crtc_update_dlist().

	 */

	drm_crtc_vblank_on(crtc);

	vc4_crtc_update_dlist(crtc);



	/* Turn on the scaler, which will wait for vstart to start

	 * compositing.

	 */
@@ -541,9 +575,6 @@ static void vc4_crtc_enable(struct drm_crtc *crtc) 
	/* Turn on the pixel valve, which will emit the vstart signal. */

	CRTC_WRITE(PV_V_CONTROL,

		   CRTC_READ(PV_V_CONTROL) | PV_VCONTROL_VIDEN);



	/* Enable vblank irq handling after crtc is started. */

	drm_crtc_vblank_on(crtc);

}



static bool vc4_crtc_mode_fixup(struct drm_crtc *crtc,
@@ -598,7 +629,6 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc, 
{

	struct drm_device *dev = crtc->dev;

	struct vc4_dev *vc4 = to_vc4_dev(dev);

	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);

	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);

	struct drm_plane *plane;

	bool debug_dump_regs = false;
@@ -620,25 +650,15 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc, 


	WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size);



	if (crtc->state->event) {

		unsigned long flags;



		crtc->state->event->pipe = drm_crtc_index(crtc);



		WARN_ON(drm_crtc_vblank_get(crtc) != 0);



		spin_lock_irqsave(&dev->event_lock, flags);

		vc4_crtc->event = crtc->state->event;

		crtc->state->event = NULL;



		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),

			  vc4_state->mm.start);



		spin_unlock_irqrestore(&dev->event_lock, flags);

	} else {

		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),

			  vc4_state->mm.start);

	}

	/* Only update DISPLIST if the CRTC was already running and is not

	 * being disabled.

	 * vc4_crtc_enable() takes care of updating the dlist just after

	 * re-enabling VBLANK interrupts and before enabling the engine.

	 * If the CRTC is being disabled, there's no point in updating this

	 * information.

	 */

	if (crtc->state->active && old_state->active)

		vc4_crtc_update_dlist(crtc);



	if (debug_dump_regs) {

		DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc));