Commit d208261e authored by Jason-JH Lin's avatar Jason-JH Lin Committed by Chun-Kuang Hu
Browse files

drm/mediatek: Add wait_event_timeout when disabling plane 



Our hardware registers are set through GCE, not by the CPU.
DRM might assume the hardware is disabled immediately after calling
atomic_disable() of drm_plane, but it is only truly disabled after the
GCE IRQ is triggered.

Additionally, the cursor plane in DRM uses async_commit, so DRM will
not wait for vblank and will free the buffer immediately after calling
atomic_disable().

To prevent the framebuffer from being freed before the layer disable
settings are configured into the hardware, which can cause an IOMMU
fault error, a wait_event_timeout has been added to wait for the
ddp_cmdq_cb() callback,indicating that the GCE IRQ has been triggered.

Fixes: 2f965be7 ("drm/mediatek: apply CMDQ control flow")
Signed-off-by: default avatarJason-JH Lin <jason-jh.lin@mediatek.com>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: default avatarCK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20250624113223.443274-1-jason-jh.lin@mediatek.com/


Signed-off-by: default avatarChun-Kuang Hu <chunkuang.hu@kernel.org>
parent 19272b37

drivers/gpu/drm/mediatek/mtk_crtc.c

+33 −0
Original line number Diff line number Diff line
@@ -719,6 +719,39 @@ int mtk_crtc_plane_check(struct drm_crtc *crtc, struct drm_plane *plane, 
	return 0;

}



void mtk_crtc_plane_disable(struct drm_crtc *crtc, struct drm_plane *plane)

{

#if IS_REACHABLE(CONFIG_MTK_CMDQ)

	struct mtk_crtc *mtk_crtc = to_mtk_crtc(crtc);

	struct mtk_plane_state *plane_state = to_mtk_plane_state(plane->state);

	int i;



	/* no need to wait for disabling the plane by CPU */

	if (!mtk_crtc->cmdq_client.chan)

		return;



	if (!mtk_crtc->enabled)

		return;



	/* set pending plane state to disabled */

	for (i = 0; i < mtk_crtc->layer_nr; i++) {

		struct drm_plane *mtk_plane = &mtk_crtc->planes[i];

		struct mtk_plane_state *mtk_plane_state = to_mtk_plane_state(mtk_plane->state);



		if (mtk_plane->index == plane->index) {

			memcpy(mtk_plane_state, plane_state, sizeof(*plane_state));

			break;

		}

	}

	mtk_crtc_update_config(mtk_crtc, false);



	/* wait for planes to be disabled by CMDQ */

	wait_event_timeout(mtk_crtc->cb_blocking_queue,

			   mtk_crtc->cmdq_vblank_cnt == 0,

			   msecs_to_jiffies(500));

#endif

}



void mtk_crtc_async_update(struct drm_crtc *crtc, struct drm_plane *plane,

			   struct drm_atomic_state *state)

{

drivers/gpu/drm/mediatek/mtk_crtc.h

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ int mtk_crtc_create(struct drm_device *drm_dev, const unsigned int *path, 
		    unsigned int num_conn_routes);

int mtk_crtc_plane_check(struct drm_crtc *crtc, struct drm_plane *plane,

			 struct mtk_plane_state *state);

void mtk_crtc_plane_disable(struct drm_crtc *crtc, struct drm_plane *plane);

void mtk_crtc_async_update(struct drm_crtc *crtc, struct drm_plane *plane,

			   struct drm_atomic_state *plane_state);

struct device *mtk_crtc_dma_dev_get(struct drm_crtc *crtc);

drivers/gpu/drm/mediatek/mtk_plane.c

+5 −0
Original line number Diff line number Diff line
@@ -285,9 +285,14 @@ static void mtk_plane_atomic_disable(struct drm_plane *plane, 
	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,

									   plane);

	struct mtk_plane_state *mtk_plane_state = to_mtk_plane_state(new_state);

	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,

									   plane);



	mtk_plane_state->pending.enable = false;

	wmb(); /* Make sure the above parameter is set before update */

	mtk_plane_state->pending.dirty = true;



	mtk_crtc_plane_disable(old_state->crtc, plane);

}



static void mtk_plane_atomic_update(struct drm_plane *plane,