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

Fixes: 41016fe1028e ("drm: Rename plane->state variables in atomic update and 
disable")
Signed-off-by: Yongqiang Niu <yongqiang....@mediatek.com>
---
 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.s...@mediatek.com>");
 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 {
-- 
2.25.1

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