diff mbox series

[v2] drm/mediatek: Fix missing configuration flags in mtk_crtc_ddp_config()

Message ID 20240819-drm-fixup-0819-v2-1-a03580ece3ec@mediatek.com (mailing list archive)
State New, archived
Headers show
Series [v2] drm/mediatek: Fix missing configuration flags in mtk_crtc_ddp_config() | expand

Commit Message

Jason-JH.Lin via B4 Relay Aug. 19, 2024, 3:25 p.m. UTC 
From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>

In mtk_crtc_ddp_config(), mtk_crtc will use some configuration flags to
generate instructions to cmdq_handle, such as:
  state->pending_config
  mtk_crtc->pending_planes
  plane_state->pending.config
  mtk_crtc->pending_async_planes
  plane_state->pending.async_config

These configuration flags may be set to false when a GCE IRQ comes calling
ddp_cmdq_cb(). This may result in missing prepare instructions,
especially if mtk_crtc_update_config() with the flase need_vblank (no need
to wait for vblank) cases.

Therefore, the mtk_crtc->config_updating flag is set at the beginning of
mtk_crtc_update_config() to ensure that these configuration flags won't be
changed when the mtk_crtc_ddp_config() is preparing instructions.
But somehow the ddp_cmdq_cb() didn't use the mtk_crtc->config_updating
flag to prevent those pending config flags from being cleared.

To avoid missing the configuration when generating the config instruction,
the config_updating flag should be added into ddp_cmdq_cb() and be
protected with spin_lock.

Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
---
Change in v2:
Add spin_lock protection for config_updating flag.
---
 drivers/gpu/drm/mediatek/mtk_crtc.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)


---
base-commit: 469f1bad3c1c6e268059f78c0eec7e9552b3894c
change-id: 20240819-drm-fixup-0819-f51e2d37fcd7

Best regards,

Comments

CK Hu (胡俊光) Aug. 20, 2024, 5:56 a.m. UTC | #1 
Hi, Jason:

On Mon, 2024-08-19 at 23:25 +0800, Jason-JH.Lin via B4 Relay wrote:
>  	 
> External email : Please do not click links or open attachments until you have verified the sender or the content.
>  From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>
> 
> In mtk_crtc_ddp_config(), mtk_crtc will use some configuration flags to
> generate instructions to cmdq_handle, such as:
>   state->pending_config
>   mtk_crtc->pending_planes
>   plane_state->pending.config
>   mtk_crtc->pending_async_planes
>   plane_state->pending.async_config
> 
> These configuration flags may be set to false when a GCE IRQ comes calling
> ddp_cmdq_cb(). This may result in missing prepare instructions,
> especially if mtk_crtc_update_config() with the flase need_vblank (no need
> to wait for vblank) cases.
> 
> Therefore, the mtk_crtc->config_updating flag is set at the beginning of
> mtk_crtc_update_config() to ensure that these configuration flags won't be
> changed when the mtk_crtc_ddp_config() is preparing instructions.
> But somehow the ddp_cmdq_cb() didn't use the mtk_crtc->config_updating
> flag to prevent those pending config flags from being cleared.
> 
> To avoid missing the configuration when generating the config instruction,
> the config_updating flag should be added into ddp_cmdq_cb() and be
> protected with spin_lock.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done")
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> ---
> Change in v2:
> Add spin_lock protection for config_updating flag.
> ---
>  drivers/gpu/drm/mediatek/mtk_crtc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
> index 6f34f573e127..b752c0b46383 100644
> --- a/drivers/gpu/drm/mediatek/mtk_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
> @@ -69,6 +69,8 @@ struct mtk_crtc {
>  /* lock for display hardware access */
>  struct mutexhw_lock;
>  boolconfig_updating;
> +/* lock for config_updating to cmd buffer */
> +spinlock_tconfig_lock;
>  };
>  
>  struct mtk_crtc_state {
> @@ -107,10 +109,13 @@ static void mtk_crtc_finish_page_flip(struct mtk_crtc *mtk_crtc)
>  static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc)
>  {
>  drm_crtc_handle_vblank(&mtk_crtc->base);
> +
> +spin_lock(&mtk_crtc->config_lock);
>  if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) {
>  mtk_crtc_finish_page_flip(mtk_crtc);
>  mtk_crtc->pending_needs_vblank = false;
>  }
> +spin_unlock(&mtk_crtc->config_lock);
>  }
>  
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> @@ -314,6 +319,13 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
>  
>  state = to_mtk_crtc_state(mtk_crtc->base.state);
>  
> +spin_lock(&mtk_crtc->config_lock);
> +
> +if (mtk_crtc->config_updating) {
> +spin_unlock(&mtk_crtc->config_lock);
> +goto ddp_cmdq_cb_out;
> +}
> +
>  state->pending_config = false;
>  
>  if (mtk_crtc->pending_planes) {
> @@ -340,6 +352,10 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
>  mtk_crtc->pending_async_planes = false;
>  }
>  
> +spin_unlock(&mtk_crtc->config_lock);
> +
> +ddp_cmdq_cb_out:
> +
>  mtk_crtc->cmdq_vblank_cnt = 0;
>  wake_up(&mtk_crtc->cb_blocking_queue);
>  }
> @@ -571,7 +587,11 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
>  int i;
>  
>  mutex_lock(&mtk_crtc->hw_lock);
> +
> +spin_lock(&mtk_crtc->config_lock);
>  mtk_crtc->config_updating = true;
> +spin_unlock(&mtk_crtc->config_lock);
> +
>  if (needs_vblank)
>  mtk_crtc->pending_needs_vblank = true;
>  
> @@ -625,7 +645,10 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
>  mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
>  }
>  #endif
> +spin_lock(&mtk_crtc->config_lock);
>  mtk_crtc->config_updating = false;
> +spin_unlock(&mtk_crtc->config_lock);
> +
>  mutex_unlock(&mtk_crtc->hw_lock);
>  }
>  
> @@ -1068,6 +1091,7 @@ int mtk_crtc_create(struct drm_device *drm_dev, const unsigned int *path,
>  drm_mode_crtc_set_gamma_size(&mtk_crtc->base, gamma_lut_size);
>  drm_crtc_enable_color_mgmt(&mtk_crtc->base, 0, has_ctm, gamma_lut_size);
>  mutex_init(&mtk_crtc->hw_lock);
> +spin_lock_init(&mtk_crtc->config_lock);
>  
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>  i = priv->mbox_index++;
> 
> ---
> base-commit: 469f1bad3c1c6e268059f78c0eec7e9552b3894c
> change-id: 20240819-drm-fixup-0819-f51e2d37fcd7
> 
> Best regards,
> -- 
> Jason-JH.Lin <jason-jh.lin@mediatek.com>
> 
>
Chun-Kuang Hu Aug. 22, 2024, 2:16 p.m. UTC | #2 
Hi, Jason:

Jason-JH.Lin via B4 Relay
<devnull+jason-jh.lin.mediatek.com@kernel.org> 於 2024年8月19日 週一
下午11:26寫道：
>
> From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>
>
> In mtk_crtc_ddp_config(), mtk_crtc will use some configuration flags to
> generate instructions to cmdq_handle, such as:
>   state->pending_config
>   mtk_crtc->pending_planes
>   plane_state->pending.config
>   mtk_crtc->pending_async_planes
>   plane_state->pending.async_config
>
> These configuration flags may be set to false when a GCE IRQ comes calling
> ddp_cmdq_cb(). This may result in missing prepare instructions,
> especially if mtk_crtc_update_config() with the flase need_vblank (no need
> to wait for vblank) cases.
>
> Therefore, the mtk_crtc->config_updating flag is set at the beginning of
> mtk_crtc_update_config() to ensure that these configuration flags won't be
> changed when the mtk_crtc_ddp_config() is preparing instructions.
> But somehow the ddp_cmdq_cb() didn't use the mtk_crtc->config_updating
> flag to prevent those pending config flags from being cleared.
>
> To avoid missing the configuration when generating the config instruction,
> the config_updating flag should be added into ddp_cmdq_cb() and be
> protected with spin_lock.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

>
> Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done")
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> ---
> Change in v2:
> Add spin_lock protection for config_updating flag.
> ---
>  drivers/gpu/drm/mediatek/mtk_crtc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
> index 6f34f573e127..b752c0b46383 100644
> --- a/drivers/gpu/drm/mediatek/mtk_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
> @@ -69,6 +69,8 @@ struct mtk_crtc {
>         /* lock for display hardware access */
>         struct mutex                    hw_lock;
>         bool                            config_updating;
> +       /* lock for config_updating to cmd buffer */
> +       spinlock_t                      config_lock;
>  };
>
>  struct mtk_crtc_state {
> @@ -107,10 +109,13 @@ static void mtk_crtc_finish_page_flip(struct mtk_crtc *mtk_crtc)
>  static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc)
>  {
>         drm_crtc_handle_vblank(&mtk_crtc->base);
> +
> +       spin_lock(&mtk_crtc->config_lock);
>         if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) {
>                 mtk_crtc_finish_page_flip(mtk_crtc);
>                 mtk_crtc->pending_needs_vblank = false;
>         }
> +       spin_unlock(&mtk_crtc->config_lock);
>  }
>
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> @@ -314,6 +319,13 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
>
>         state = to_mtk_crtc_state(mtk_crtc->base.state);
>
> +       spin_lock(&mtk_crtc->config_lock);
> +
> +       if (mtk_crtc->config_updating) {
> +               spin_unlock(&mtk_crtc->config_lock);
> +               goto ddp_cmdq_cb_out;
> +       }
> +
>         state->pending_config = false;
>
>         if (mtk_crtc->pending_planes) {
> @@ -340,6 +352,10 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
>                 mtk_crtc->pending_async_planes = false;
>         }
>
> +       spin_unlock(&mtk_crtc->config_lock);
> +
> +ddp_cmdq_cb_out:
> +
>         mtk_crtc->cmdq_vblank_cnt = 0;
>         wake_up(&mtk_crtc->cb_blocking_queue);
>  }
> @@ -571,7 +587,11 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
>         int i;
>
>         mutex_lock(&mtk_crtc->hw_lock);
> +
> +       spin_lock(&mtk_crtc->config_lock);
>         mtk_crtc->config_updating = true;
> +       spin_unlock(&mtk_crtc->config_lock);
> +
>         if (needs_vblank)
>                 mtk_crtc->pending_needs_vblank = true;
>
> @@ -625,7 +645,10 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
>                 mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
>         }
>  #endif
> +       spin_lock(&mtk_crtc->config_lock);
>         mtk_crtc->config_updating = false;
> +       spin_unlock(&mtk_crtc->config_lock);
> +
>         mutex_unlock(&mtk_crtc->hw_lock);
>  }
>
> @@ -1068,6 +1091,7 @@ int mtk_crtc_create(struct drm_device *drm_dev, const unsigned int *path,
>                 drm_mode_crtc_set_gamma_size(&mtk_crtc->base, gamma_lut_size);
>         drm_crtc_enable_color_mgmt(&mtk_crtc->base, 0, has_ctm, gamma_lut_size);
>         mutex_init(&mtk_crtc->hw_lock);
> +       spin_lock_init(&mtk_crtc->config_lock);
>
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>         i = priv->mbox_index++;
>
> ---
> base-commit: 469f1bad3c1c6e268059f78c0eec7e9552b3894c
> change-id: 20240819-drm-fixup-0819-f51e2d37fcd7
>
> Best regards,
> --
> Jason-JH.Lin <jason-jh.lin@mediatek.com>
>
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
index 6f34f573e127..b752c0b46383 100644
--- a/drivers/gpu/drm/mediatek/mtk_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
@@ -69,6 +69,8 @@  struct mtk_crtc {
 	/* lock for display hardware access */
 	struct mutex			hw_lock;
 	bool				config_updating;
+	/* lock for config_updating to cmd buffer */
+	spinlock_t			config_lock;
 };
 
 struct mtk_crtc_state {
@@ -107,10 +109,13 @@  static void mtk_crtc_finish_page_flip(struct mtk_crtc *mtk_crtc)
 static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc)
 {
 	drm_crtc_handle_vblank(&mtk_crtc->base);
+
+	spin_lock(&mtk_crtc->config_lock);
 	if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) {
 		mtk_crtc_finish_page_flip(mtk_crtc);
 		mtk_crtc->pending_needs_vblank = false;
 	}
+	spin_unlock(&mtk_crtc->config_lock);
 }
 
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
@@ -314,6 +319,13 @@  static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 
 	state = to_mtk_crtc_state(mtk_crtc->base.state);
 
+	spin_lock(&mtk_crtc->config_lock);
+
+	if (mtk_crtc->config_updating) {
+		spin_unlock(&mtk_crtc->config_lock);
+		goto ddp_cmdq_cb_out;
+	}
+
 	state->pending_config = false;
 
 	if (mtk_crtc->pending_planes) {
@@ -340,6 +352,10 @@  static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 		mtk_crtc->pending_async_planes = false;
 	}
 
+	spin_unlock(&mtk_crtc->config_lock);
+
+ddp_cmdq_cb_out:
+
 	mtk_crtc->cmdq_vblank_cnt = 0;
 	wake_up(&mtk_crtc->cb_blocking_queue);
 }
@@ -571,7 +587,11 @@  static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
 	int i;
 
 	mutex_lock(&mtk_crtc->hw_lock);
+
+	spin_lock(&mtk_crtc->config_lock);
 	mtk_crtc->config_updating = true;
+	spin_unlock(&mtk_crtc->config_lock);
+
 	if (needs_vblank)
 		mtk_crtc->pending_needs_vblank = true;
 
@@ -625,7 +645,10 @@  static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
 		mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
 	}
 #endif
+	spin_lock(&mtk_crtc->config_lock);
 	mtk_crtc->config_updating = false;
+	spin_unlock(&mtk_crtc->config_lock);
+
 	mutex_unlock(&mtk_crtc->hw_lock);
 }
 
@@ -1068,6 +1091,7 @@  int mtk_crtc_create(struct drm_device *drm_dev, const unsigned int *path,
 		drm_mode_crtc_set_gamma_size(&mtk_crtc->base, gamma_lut_size);
 	drm_crtc_enable_color_mgmt(&mtk_crtc->base, 0, has_ctm, gamma_lut_size);
 	mutex_init(&mtk_crtc->hw_lock);
+	spin_lock_init(&mtk_crtc->config_lock);
 
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
 	i = priv->mbox_index++;