Hi, Yongqiang:
On Tue, 2023-11-21 at 14:50 +0800, Yongqiang Niu wrote:
> the DMA buffer is released when still accessed by Mediatek display
> hardware,
> this flow can lead to M4U reporting a translation fault warning
>
> add dma buffer control flow in mediatek driver:
> get dma buffer when drm plane disable
> put dma buffer when overlay really disable
In drm_atomic_helper_commit(), it call
drm_atomic_helper_wait_for_vblanks(). And I think this would make sure
that setting has been applied to hardware. So you don't need to modify
mtk_plane_atomic_disable(). If there is bug in
drm_atomic_helper_wait_for_vblanks(), fix
drm_atomic_helper_wait_for_vblanks().
Regards,
CK
>
> Fixes: 41016fe1028e ("drm: Rename plane->state variables in atomic
> update and disable")
> Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 25
> ++++++++++++++++++++++++
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 1 +
> drivers/gpu/drm/mediatek/mtk_drm_plane.c | 12 ++++++++++++
> drivers/gpu/drm/mediatek/mtk_drm_plane.h | 1 +
> 4 files changed, 39 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index c277b9fae950..188aaa97e5e3 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -4,6 +4,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/dma-buf.h>
> #include <linux/dma-mapping.h>
> #include <linux/mailbox_controller.h>
> #include <linux/of.h>
> @@ -283,6 +284,23 @@ struct mtk_ddp_comp
> *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
> return NULL;
> }
>
> +static void mtk_drm_dma_buf_put(struct mtk_drm_crtc *mtk_crtc)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < mtk_crtc->layer_nr; i++) {
> + struct drm_plane *plane = &mtk_crtc->planes[i];
> + struct mtk_plane_state *plane_state;
> +
> + plane_state = to_mtk_plane_state(plane->state);
> +
> + if (plane_state && plane_state->pending.dma_buf) {
> + dma_buf_put(plane_state->pending.dma_buf);
> + plane_state->pending.dma_buf = NULL;
> + }
> + }
> +}
> +
> #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
> {
> @@ -323,6 +341,8 @@ static void ddp_cmdq_cb(struct mbox_client *cl,
> void *mssg)
> mtk_crtc->pending_async_planes = false;
> }
>
> + mtk_drm_dma_buf_put(mtk_crtc);
> +
> mtk_crtc->cmdq_vblank_cnt = 0;
> wake_up(&mtk_crtc->cb_blocking_queue);
> }
> @@ -627,9 +647,14 @@ static void mtk_crtc_ddp_irq(void *data)
> else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc-
> >cmdq_vblank_cnt == 0)
> DRM_ERROR("mtk_crtc %d CMDQ execute command
> timeout!\n",
> drm_crtc_index(&mtk_crtc->base));
> +
> + if (!mtk_crtc->cmdq_client.chan)
> + mtk_drm_dma_buf_put(mtk_crtc);
> #else
> if (!priv->data->shadow_register)
> mtk_crtc_ddp_config(crtc, NULL);
> +
> + mtk_drm_dma_buf_put(mtk_crtc);
> #endif
> mtk_drm_finish_page_flip(mtk_crtc);
> }
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 2dfaa613276a..4fd232644383 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -1019,4 +1019,5 @@ module_exit(mtk_drm_exit);
>
> MODULE_AUTHOR("YT SHEN <yt.shen@xxxxxxxxxxxx>");
> MODULE_DESCRIPTION("Mediatek SoC DRM driver");
> +MODULE_IMPORT_NS(DMA_BUF);
> MODULE_LICENSE("GPL v2");
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> index ddc9355b06d5..fbfcd0d1a56c 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> @@ -12,6 +12,7 @@
> #include <drm/drm_framebuffer.h>
> #include <drm/drm_gem_atomic_helper.h>
> #include <linux/align.h>
> +#include <linux/dma-buf.h>
>
> #include "mtk_drm_crtc.h"
> #include "mtk_drm_ddp_comp.h"
> @@ -283,6 +284,17 @@ 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);
> +
> + if (old_state && old_state->fb) {
> + struct drm_gem_object *gem = old_state->fb->obj[0];
> +
> + if (gem && gem->dma_buf) {
> + get_dma_buf(gem->dma_buf);
> + mtk_plane_state->pending.dma_buf = gem-
> >dma_buf;
> + }
> + }
> mtk_plane_state->pending.enable = false;
> wmb(); /* Make sure the above parameter is set before update */
> mtk_plane_state->pending.dirty = true;
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.h
> b/drivers/gpu/drm/mediatek/mtk_drm_plane.h
> index 99aff7da0831..3aba0b58ef3c 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_plane.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.h
> @@ -33,6 +33,7 @@ struct mtk_plane_pending_state {
> bool async_dirty;
> bool async_config;
> enum drm_color_encoding color_encoding;
> + struct dma_buf *dma_buf;
> };
>
> struct mtk_plane_state {
