[PATCH v4 1/2] drm/mediatek: fix kernel oops if no crtc is found

[PATCH v4 1/2] drm/mediatek: fix kernel oops if no crtc is found

[Michael Walle]

drm_crtc_from_index(0) might return NULL if there are no CRTCs
registered at all which will lead to a kernel oops in
mtk_drm_crtc_dma_dev_get(). Add the missing return value check.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
v4:
 - collected tags
v3:
 - none
v2:
 - collected tags
 - fixed typos
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 93552d76b6e7..2c582498817e 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -420,6 +420,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
 	struct mtk_drm_private *private = drm->dev_private;
 	struct mtk_drm_private *priv_n;
 	struct device *dma_dev = NULL;
+	struct drm_crtc *crtc;
 	int ret, i, j;
 
 	if (drm_firmware_drivers_only())
@@ -494,7 +495,9 @@ static int mtk_drm_kms_init(struct drm_device *drm)
 	}
 
 	/* Use OVL device for all DMA memory allocations */
-	dma_dev = mtk_drm_crtc_dma_dev_get(drm_crtc_from_index(drm, 0));
+	crtc = drm_crtc_from_index(drm, 0);
+	if (crtc)
+		dma_dev = mtk_drm_crtc_dma_dev_get(crtc);
 	if (!dma_dev) {
 		ret = -ENODEV;
 		dev_err(drm->dev, "Need at least one OVL device\n");
-- 
2.39.2


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[PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Michael Walle]

mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
always have the CRTC with id 0, the ext id 1 and the third id 2. This
is only true if the paths are all available. But paths are optional (see
also comment in mtk_drm_kms_init()), e.g. the main path might not be
enabled or available at all. Then the CRTC IDs will shift one up, e.g.
ext will be 0 and the third path will be 1.

To fix that, dynamically calculate the IDs by the presence of the paths.

While at it, make the return code a signed one and return -ENOENT if no
path is found and handle the error in the callers.

Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting possible_crtc way")
Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
---
v4:
 - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
   any path
v3:
 - use data instead of priv_n->data
 - fixed typos
 - collected Rb and Tb tags
v2:
 - iterate over all_drm_private[] to get any vdosys
 - new check if a path is available
---
 drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
 drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
 4 files changed, 68 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index 2f931e4e2b60..f9250f7ee706 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct device *master, void *data)
 		return ret;
 	}
 
-	dpi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
+	ret = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
+	if (ret < 0)
+		goto err_cleanup;
+	dpi->encoder.possible_crtcs = ret;
 
 	ret = drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
 				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
index 771f4e173353..83ae75ecd858 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
@@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device *dev,
 	return false;
 }
 
+static bool mtk_ddp_path_available(const unsigned int *path,
+				   unsigned int path_len,
+				   struct device_node **comp_node)
+{
+	unsigned int i;
+
+	if (!path)
+		return false;
+
+	for (i = 0U; i < path_len; i++) {
+		/* OVL_ADAPTOR doesn't have a device node */
+		if (path[i] == DDP_COMPONENT_DRM_OVL_ADAPTOR)
+			continue;
+
+		if (!comp_node[path[i]])
+			return false;
+	}
+
+	return true;
+}
+
 int mtk_ddp_comp_get_id(struct device_node *node,
 			enum mtk_ddp_comp_type comp_type)
 {
@@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
 	return -EINVAL;
 }
 
-unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
-						struct device *dev)
+int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev)
 {
 	struct mtk_drm_private *private = drm->dev_private;
-	unsigned int ret = 0;
-
-	if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path, private->data->main_len,
-				     private->ddp_comp))
-		ret = BIT(0);
-	else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
-					  private->data->ext_len, private->ddp_comp))
-		ret = BIT(1);
-	else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
-					  private->data->third_len, private->ddp_comp))
-		ret = BIT(2);
-	else
-		DRM_INFO("Failed to find comp in ddp table\n");
+	const struct mtk_mmsys_driver_data *data;
+	struct mtk_drm_private *priv_n;
+	int i = 0, j;
+
+	for (j = 0; j < private->data->mmsys_dev_num; j++) {
+		priv_n = private->all_drm_private[j];
+		data = priv_n->data;
+
+		if (mtk_ddp_path_available(data->main_path, data->main_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->main_path,
+						     data->main_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+
+		if (mtk_ddp_path_available(data->ext_path, data->ext_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
+						     data->ext_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+
+		if (mtk_ddp_path_available(data->third_path, data->third_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->third_path,
+						     data->third_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+	}
 
-	return ret;
+	DRM_INFO("Failed to find comp in ddp table\n");
+	return -ENOENT;
 }
 
 int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp *comp,
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
index febcaeef16a1..6a95df72de0a 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
@@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct mtk_ddp_comp *comp, struct dev
 
 int mtk_ddp_comp_get_id(struct device_node *node,
 			enum mtk_ddp_comp_type comp_type);
-unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
-						struct device *dev);
+int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev);
 int mtk_ddp_comp_init(struct device_node *comp_node, struct mtk_ddp_comp *comp,
 		      unsigned int comp_id);
 enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index d8bfc2cce54d..d67e5c61a9b9 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
 		return ret;
 	}
 
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+	ret = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+	if (ret < 0)
+		goto err_cleanup_encoder;
+	dsi->encoder.possible_crtcs = ret;
 
 	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
 				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-- 
2.39.2


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Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[AngeloGioacchino Del Regno]

Il 05/09/23 10:49, Michael Walle ha scritto:
> mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
> always have the CRTC with id 0, the ext id 1 and the third id 2. This
> is only true if the paths are all available. But paths are optional (see
> also comment in mtk_drm_kms_init()), e.g. the main path might not be
> enabled or available at all. Then the CRTC IDs will shift one up, e.g.
> ext will be 0 and the third path will be 1.
> 
> To fix that, dynamically calculate the IDs by the presence of the paths.
> 
> While at it, make the return code a signed one and return -ENOENT if no
> path is found and handle the error in the callers.
> 
> Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting possible_crtc way")
> Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Perfect!

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

> ---
> v4:
>   - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
>     any path
> v3:
>   - use data instead of priv_n->data
>   - fixed typos
>   - collected Rb and Tb tags
> v2:
>   - iterate over all_drm_private[] to get any vdosys
>   - new check if a path is available
> ---
>   drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
>   drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
>   drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
>   drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
>   4 files changed, 68 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 2f931e4e2b60..f9250f7ee706 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct device *master, void *data)
>   		return ret;
>   	}
>   
> -	dpi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> +	ret = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> +	if (ret < 0)
> +		goto err_cleanup;
> +	dpi->encoder.possible_crtcs = ret;
>   
>   	ret = drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
>   				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index 771f4e173353..83ae75ecd858 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device *dev,
>   	return false;
>   }
>   
> +static bool mtk_ddp_path_available(const unsigned int *path,
> +				   unsigned int path_len,
> +				   struct device_node **comp_node)
> +{
> +	unsigned int i;
> +
> +	if (!path)
> +		return false;
> +
> +	for (i = 0U; i < path_len; i++) {
> +		/* OVL_ADAPTOR doesn't have a device node */
> +		if (path[i] == DDP_COMPONENT_DRM_OVL_ADAPTOR)
> +			continue;
> +
> +		if (!comp_node[path[i]])
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
>   int mtk_ddp_comp_get_id(struct device_node *node,
>   			enum mtk_ddp_comp_type comp_type)
>   {
> @@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
>   	return -EINVAL;
>   }
>   
> -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
> -						struct device *dev)
> +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev)
>   {
>   	struct mtk_drm_private *private = drm->dev_private;
> -	unsigned int ret = 0;
> -
> -	if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path, private->data->main_len,
> -				     private->ddp_comp))
> -		ret = BIT(0);
> -	else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
> -					  private->data->ext_len, private->ddp_comp))
> -		ret = BIT(1);
> -	else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
> -					  private->data->third_len, private->ddp_comp))
> -		ret = BIT(2);
> -	else
> -		DRM_INFO("Failed to find comp in ddp table\n");
> +	const struct mtk_mmsys_driver_data *data;
> +	struct mtk_drm_private *priv_n;
> +	int i = 0, j;
> +
> +	for (j = 0; j < private->data->mmsys_dev_num; j++) {
> +		priv_n = private->all_drm_private[j];
> +		data = priv_n->data;
> +
> +		if (mtk_ddp_path_available(data->main_path, data->main_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->main_path,
> +						     data->main_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +
> +		if (mtk_ddp_path_available(data->ext_path, data->ext_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
> +						     data->ext_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +
> +		if (mtk_ddp_path_available(data->third_path, data->third_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->third_path,
> +						     data->third_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +	}
>   
> -	return ret;
> +	DRM_INFO("Failed to find comp in ddp table\n");
> +	return -ENOENT;
>   }
>   
>   int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp *comp,
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> index febcaeef16a1..6a95df72de0a 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> @@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct mtk_ddp_comp *comp, struct dev
>   
>   int mtk_ddp_comp_get_id(struct device_node *node,
>   			enum mtk_ddp_comp_type comp_type);
> -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
> -						struct device *dev);
> +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev);
>   int mtk_ddp_comp_init(struct device_node *comp_node, struct mtk_ddp_comp *comp,
>   		      unsigned int comp_id);
>   enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index d8bfc2cce54d..d67e5c61a9b9 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
>   		return ret;
>   	}
>   
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +	ret = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +	if (ret < 0)
> +		goto err_cleanup_encoder;
> +	dsi->encoder.possible_crtcs = ret;
>   
>   	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
>   				DRM_BRIDGE_ATTACH_NO_CONNECTOR);


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Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Michael Walle]

Hi,

> mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
> always have the CRTC with id 0, the ext id 1 and the third id 2. This
> is only true if the paths are all available. But paths are optional 
> (see
> also comment in mtk_drm_kms_init()), e.g. the main path might not be
> enabled or available at all. Then the CRTC IDs will shift one up, e.g.
> ext will be 0 and the third path will be 1.
> 
> To fix that, dynamically calculate the IDs by the presence of the 
> paths.
> 
> While at it, make the return code a signed one and return -ENOENT if no
> path is found and handle the error in the callers.
> 
> Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting 
> possible_crtc way")
> Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Is there anything wrong with these two patches? They are now lingering
around for more than two months.

Unfortunately, patch 2/2 won't apply anymore because of commit
01389b324c97 ("drm/mediatek: Add connector dynamic selection
capability). And I'm a bit puzzled for what the crtc_id is used
there because I guess it will have the same problem this patch
fixes.

-michael

> ---
> v4:
>  - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
>    any path
> v3:
>  - use data instead of priv_n->data
>  - fixed typos
>  - collected Rb and Tb tags
> v2:
>  - iterate over all_drm_private[] to get any vdosys
>  - new check if a path is available
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
>  drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
>  4 files changed, 68 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c 
> b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 2f931e4e2b60..f9250f7ee706 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct 
> device *master, void *data)
>  		return ret;
>  	}
> 
> -	dpi->encoder.possible_crtcs = 
> mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> +	ret = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> +	if (ret < 0)
> +		goto err_cleanup;
> +	dpi->encoder.possible_crtcs = ret;
> 
>  	ret = drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
>  				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c 
> b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index 771f4e173353..83ae75ecd858 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device 
> *dev,
>  	return false;
>  }
> 
> +static bool mtk_ddp_path_available(const unsigned int *path,
> +				   unsigned int path_len,
> +				   struct device_node **comp_node)
> +{
> +	unsigned int i;
> +
> +	if (!path)
> +		return false;
> +
> +	for (i = 0U; i < path_len; i++) {
> +		/* OVL_ADAPTOR doesn't have a device node */
> +		if (path[i] == DDP_COMPONENT_DRM_OVL_ADAPTOR)
> +			continue;
> +
> +		if (!comp_node[path[i]])
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
>  int mtk_ddp_comp_get_id(struct device_node *node,
>  			enum mtk_ddp_comp_type comp_type)
>  {
> @@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
>  	return -EINVAL;
>  }
> 
> -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device 
> *drm,
> -						struct device *dev)
> +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct 
> device *dev)
>  {
>  	struct mtk_drm_private *private = drm->dev_private;
> -	unsigned int ret = 0;
> -
> -	if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path, 
> private->data->main_len,
> -				     private->ddp_comp))
> -		ret = BIT(0);
> -	else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
> -					  private->data->ext_len, private->ddp_comp))
> -		ret = BIT(1);
> -	else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
> -					  private->data->third_len, private->ddp_comp))
> -		ret = BIT(2);
> -	else
> -		DRM_INFO("Failed to find comp in ddp table\n");
> +	const struct mtk_mmsys_driver_data *data;
> +	struct mtk_drm_private *priv_n;
> +	int i = 0, j;
> +
> +	for (j = 0; j < private->data->mmsys_dev_num; j++) {
> +		priv_n = private->all_drm_private[j];
> +		data = priv_n->data;
> +
> +		if (mtk_ddp_path_available(data->main_path, data->main_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->main_path,
> +						     data->main_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +
> +		if (mtk_ddp_path_available(data->ext_path, data->ext_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
> +						     data->ext_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +
> +		if (mtk_ddp_path_available(data->third_path, data->third_len,
> +					   priv_n->comp_node)) {
> +			if (mtk_drm_find_comp_in_ddp(dev, data->third_path,
> +						     data->third_len,
> +						     priv_n->ddp_comp))
> +				return BIT(i);
> +			i++;
> +		}
> +	}
> 
> -	return ret;
> +	DRM_INFO("Failed to find comp in ddp table\n");
> +	return -ENOENT;
>  }
> 
>  int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp 
> *comp,
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h 
> b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> index febcaeef16a1..6a95df72de0a 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> @@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct 
> mtk_ddp_comp *comp, struct dev
> 
>  int mtk_ddp_comp_get_id(struct device_node *node,
>  			enum mtk_ddp_comp_type comp_type);
> -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device 
> *drm,
> -						struct device *dev);
> +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct 
> device *dev);
>  int mtk_ddp_comp_init(struct device_node *comp_node, struct 
> mtk_ddp_comp *comp,
>  		      unsigned int comp_id);
>  enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c 
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index d8bfc2cce54d..d67e5c61a9b9 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device 
> *drm, struct mtk_dsi *dsi)
>  		return ret;
>  	}
> 
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, 
> dsi->host.dev);
> +	ret = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +	if (ret < 0)
> +		goto err_cleanup_encoder;
> +	dsi->encoder.possible_crtcs = ret;
> 
>  	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
>  				DRM_BRIDGE_ATTACH_NO_CONNECTOR);

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Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Chun-Kuang Hu]

Hi, Michael:

Michael Walle <mwalle@kernel.org> 於 2023年11月21日 週二 下午10:44寫道：
>
> Hi,
>
> > mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
> > always have the CRTC with id 0, the ext id 1 and the third id 2. This
> > is only true if the paths are all available. But paths are optional
> > (see
> > also comment in mtk_drm_kms_init()), e.g. the main path might not be
> > enabled or available at all. Then the CRTC IDs will shift one up, e.g.
> > ext will be 0 and the third path will be 1.
> >
> > To fix that, dynamically calculate the IDs by the presence of the
> > paths.
> >
> > While at it, make the return code a signed one and return -ENOENT if no
> > path is found and handle the error in the callers.
> >
> > Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting
> > possible_crtc way")
> > Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> > Signed-off-by: Michael Walle <mwalle@kernel.org>
> > Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> > Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>
> Is there anything wrong with these two patches? They are now lingering
> around for more than two months.
>
> Unfortunately, patch 2/2 won't apply anymore because of commit
> 01389b324c97 ("drm/mediatek: Add connector dynamic selection
> capability). And I'm a bit puzzled for what the crtc_id is used
> there because I guess it will have the same problem this patch
> fixes.

Please base on the latest kernel version to fix.

Regards,
Chun-Kuang.

>
> -michael
>
> > ---
> > v4:
> >  - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
> >    any path
> > v3:
> >  - use data instead of priv_n->data
> >  - fixed typos
> >  - collected Rb and Tb tags
> > v2:
> >  - iterate over all_drm_private[] to get any vdosys
> >  - new check if a path is available
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
> >  drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
> >  4 files changed, 68 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index 2f931e4e2b60..f9250f7ee706 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct
> > device *master, void *data)
> >               return ret;
> >       }
> >
> > -     dpi->encoder.possible_crtcs =
> > mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> > +     ret = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
> > +     if (ret < 0)
> > +             goto err_cleanup;
> > +     dpi->encoder.possible_crtcs = ret;
> >
> >       ret = drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
> >                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > index 771f4e173353..83ae75ecd858 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > @@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device
> > *dev,
> >       return false;
> >  }
> >
> > +static bool mtk_ddp_path_available(const unsigned int *path,
> > +                                unsigned int path_len,
> > +                                struct device_node **comp_node)
> > +{
> > +     unsigned int i;
> > +
> > +     if (!path)
> > +             return false;
> > +
> > +     for (i = 0U; i < path_len; i++) {
> > +             /* OVL_ADAPTOR doesn't have a device node */
> > +             if (path[i] == DDP_COMPONENT_DRM_OVL_ADAPTOR)
> > +                     continue;
> > +
> > +             if (!comp_node[path[i]])
> > +                     return false;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> >  int mtk_ddp_comp_get_id(struct device_node *node,
> >                       enum mtk_ddp_comp_type comp_type)
> >  {
> > @@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
> >       return -EINVAL;
> >  }
> >
> > -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device
> > *drm,
> > -                                             struct device *dev)
> > +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct
> > device *dev)
> >  {
> >       struct mtk_drm_private *private = drm->dev_private;
> > -     unsigned int ret = 0;
> > -
> > -     if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path,
> > private->data->main_len,
> > -                                  private->ddp_comp))
> > -             ret = BIT(0);
> > -     else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
> > -                                       private->data->ext_len, private->ddp_comp))
> > -             ret = BIT(1);
> > -     else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
> > -                                       private->data->third_len, private->ddp_comp))
> > -             ret = BIT(2);
> > -     else
> > -             DRM_INFO("Failed to find comp in ddp table\n");
> > +     const struct mtk_mmsys_driver_data *data;
> > +     struct mtk_drm_private *priv_n;
> > +     int i = 0, j;
> > +
> > +     for (j = 0; j < private->data->mmsys_dev_num; j++) {
> > +             priv_n = private->all_drm_private[j];
> > +             data = priv_n->data;
> > +
> > +             if (mtk_ddp_path_available(data->main_path, data->main_len,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->main_path,
> > +                                                  data->main_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +
> > +             if (mtk_ddp_path_available(data->ext_path, data->ext_len,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
> > +                                                  data->ext_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +
> > +             if (mtk_ddp_path_available(data->third_path, data->third_len,
> > +                                        priv_n->comp_node)) {
> > +                     if (mtk_drm_find_comp_in_ddp(dev, data->third_path,
> > +                                                  data->third_len,
> > +                                                  priv_n->ddp_comp))
> > +                             return BIT(i);
> > +                     i++;
> > +             }
> > +     }
> >
> > -     return ret;
> > +     DRM_INFO("Failed to find comp in ddp table\n");
> > +     return -ENOENT;
> >  }
> >
> >  int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp
> > *comp,
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > index febcaeef16a1..6a95df72de0a 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > @@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct
> > mtk_ddp_comp *comp, struct dev
> >
> >  int mtk_ddp_comp_get_id(struct device_node *node,
> >                       enum mtk_ddp_comp_type comp_type);
> > -unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device
> > *drm,
> > -                                             struct device *dev);
> > +int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct
> > device *dev);
> >  int mtk_ddp_comp_init(struct device_node *comp_node, struct
> > mtk_ddp_comp *comp,
> >                     unsigned int comp_id);
> >  enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index d8bfc2cce54d..d67e5c61a9b9 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device
> > *drm, struct mtk_dsi *dsi)
> >               return ret;
> >       }
> >
> > -     dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm,
> > dsi->host.dev);
> > +     ret = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> > +     if (ret < 0)
> > +             goto err_cleanup_encoder;
> > +     dsi->encoder.possible_crtcs = ret;
> >
> >       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> >                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);

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Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Michael Walle]

Hi,

>> > mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
>> > always have the CRTC with id 0, the ext id 1 and the third id 2. This
>> > is only true if the paths are all available. But paths are optional
>> > (see
>> > also comment in mtk_drm_kms_init()), e.g. the main path might not be
>> > enabled or available at all. Then the CRTC IDs will shift one up, e.g.
>> > ext will be 0 and the third path will be 1.
>> >
>> > To fix that, dynamically calculate the IDs by the presence of the
>> > paths.
>> >
>> > While at it, make the return code a signed one and return -ENOENT if no
>> > path is found and handle the error in the callers.
>> >
>> > Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting
>> > possible_crtc way")
>> > Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>> > Signed-off-by: Michael Walle <mwalle@kernel.org>
>> > Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>> > Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>> 
>> Is there anything wrong with these two patches? They are now lingering
>> around for more than two months.
>> 
>> Unfortunately, patch 2/2 won't apply anymore because of commit
>> 01389b324c97 ("drm/mediatek: Add connector dynamic selection
>> capability). And I'm a bit puzzled for what the crtc_id is used
>> there because I guess it will have the same problem this patch
>> fixes.
> 
> Please base on the latest kernel version to fix.

Of course, but the question is how to fix it. Maybe Jason-JH.Lin
can help here.

In any case, please pick patch 1/2, it's independent of the second
patch and should still apply.

-michael

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Re: [PATCH v4 1/2] drm/mediatek: fix kernel oops if no crtc is found

[Eugen Hristev]

On 9/5/23 11:49, Michael Walle wrote:
> drm_crtc_from_index(0) might return NULL if there are no CRTCs
> registered at all which will lead to a kernel oops in
> mtk_drm_crtc_dma_dev_get(). Add the missing return value check.
> 
> Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

I tried this patch as well, hit the crash during my tests. I also 
reviewed your changes

Tested-by: Eugen Hristev <eugen.hristev@collabora.com>
Reviewed-by: Eugen Hristev <eugen.hristev@collabora.com>

Eugen

> ---
> v4:
>   - collected tags
> v3:
>   - none
> v2:
>   - collected tags
>   - fixed typos
> ---
>   drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 93552d76b6e7..2c582498817e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -420,6 +420,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
>   	struct mtk_drm_private *private = drm->dev_private;
>   	struct mtk_drm_private *priv_n;
>   	struct device *dma_dev = NULL;
> +	struct drm_crtc *crtc;
>   	int ret, i, j;
>   
>   	if (drm_firmware_drivers_only())
> @@ -494,7 +495,9 @@ static int mtk_drm_kms_init(struct drm_device *drm)
>   	}
>   
>   	/* Use OVL device for all DMA memory allocations */
> -	dma_dev = mtk_drm_crtc_dma_dev_get(drm_crtc_from_index(drm, 0));
> +	crtc = drm_crtc_from_index(drm, 0);
> +	if (crtc)
> +		dma_dev = mtk_drm_crtc_dma_dev_get(crtc);
>   	if (!dma_dev) {
>   		ret = -ENODEV;
>   		dev_err(drm->dev, "Need at least one OVL device\n");


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Re: [PATCH v4 1/2] drm/mediatek: fix kernel oops if no crtc is found

[Chun-Kuang Hu]

Hi, Michael:

Michael Walle <mwalle@kernel.org> 於 2023年9月5日 週二 下午4:49寫道：
>
> drm_crtc_from_index(0) might return NULL if there are no CRTCs
> registered at all which will lead to a kernel oops in
> mtk_drm_crtc_dma_dev_get(). Add the missing return value check.

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

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

Regards,
Chun-Kuang.

>
> Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> v4:
>  - collected tags
> v3:
>  - none
> v2:
>  - collected tags
>  - fixed typos
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 93552d76b6e7..2c582498817e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -420,6 +420,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
>         struct mtk_drm_private *private = drm->dev_private;
>         struct mtk_drm_private *priv_n;
>         struct device *dma_dev = NULL;
> +       struct drm_crtc *crtc;
>         int ret, i, j;
>
>         if (drm_firmware_drivers_only())
> @@ -494,7 +495,9 @@ static int mtk_drm_kms_init(struct drm_device *drm)
>         }
>
>         /* Use OVL device for all DMA memory allocations */
> -       dma_dev = mtk_drm_crtc_dma_dev_get(drm_crtc_from_index(drm, 0));
> +       crtc = drm_crtc_from_index(drm, 0);
> +       if (crtc)
> +               dma_dev = mtk_drm_crtc_dma_dev_get(crtc);
>         if (!dma_dev) {
>                 ret = -ENODEV;
>                 dev_err(drm->dev, "Need at least one OVL device\n");
> --
> 2.39.2
>

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