diff mbox series

[11/11] drm/bridge: tc358768: Add DRM_BRIDGE_ATTACH_NO_CONNECTOR support

Message ID 20230804-tc358768-v1-11-1afd44b7826b@ideasonboard.com
State New
Headers
Series drm/bridge: tc358768: Fixes and timings improvements |

Commit Message

Tomi Valkeinen Aug. 4, 2023, 10:44 a.m. UTC 
  Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
 1 file changed, 45 insertions(+), 19 deletions(-)

Comments

Péter Ujfalusi Aug. 11, 2023, 4:44 p.m. UTC | #1 
On 04/08/2023 13:44, Tomi Valkeinen wrote:

I would rather have a commit message than a blank one.

> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
>  1 file changed, 45 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> index ea19de5509ed..a567f136ddc7 100644
> --- a/drivers/gpu/drm/bridge/tc358768.c
> +++ b/drivers/gpu/drm/bridge/tc358768.c
> @@ -131,8 +131,17 @@ static const char * const tc358768_supplies[] = {
>  
>  struct tc358768_dsi_output {
>  	struct mipi_dsi_device *dev;
> +
> +	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
>  	struct drm_panel *panel;
> -	struct drm_bridge *bridge;
> +
> +	/*
> +	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
> +	 * to tc358768, 'next_bridge' contains the bridge the driver created
> +	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
> +	 * the next bridge the driver found.
> +	 */
> +	struct drm_bridge *next_bridge;

why it is better to call it next_bridge than just bridge? Is there a
prev_bridge also?

>  };
>  
>  struct tc358768_priv {
> @@ -391,8 +400,6 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>  				    struct mipi_dsi_device *dev)
>  {
>  	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
> -	struct drm_bridge *bridge;
> -	struct drm_panel *panel;
>  	struct device_node *ep;
>  	int ret;
>  
> @@ -420,21 +427,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>  		return -ENOTSUPP;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
> -					  &bridge);
> -	if (ret)
> -		return ret;
> -
> -	if (panel) {
> -		bridge = drm_panel_bridge_add_typed(panel,
> -						    DRM_MODE_CONNECTOR_DSI);
> -		if (IS_ERR(bridge))
> -			return PTR_ERR(bridge);
> -	}
> -
>  	priv->output.dev = dev;
> -	priv->output.bridge = bridge;
> -	priv->output.panel = panel;
>  
>  	priv->dsi_lanes = dev->lanes;
>  	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
> @@ -463,7 +456,7 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>  
>  	drm_bridge_remove(&priv->bridge);
>  	if (priv->output.panel)
> -		drm_panel_bridge_remove(priv->output.bridge);
> +		drm_panel_bridge_remove(priv->output.next_bridge);
>  
>  	return 0;
>  }
> @@ -544,7 +537,40 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>  		return -ENOTSUPP;
>  	}
>  
> -	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
> +	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> +		struct device_node *node;
> +
> +		/* Get the next bridge, connected to port@1. */
> +		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
> +		if (!node)
> +			return -ENODEV;
> +
> +		priv->output.next_bridge = of_drm_find_bridge(node);
> +		of_node_put(node);
> +		if (!priv->output.next_bridge)
> +			return -EPROBE_DEFER;
> +	} else {
> +		struct drm_bridge *bridge;
> +		struct drm_panel *panel;
> +		int ret;
> +
> +		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
> +						  &panel, &bridge);
> +		if (ret)
> +			return ret;
> +
> +		if (panel) {
> +			bridge = drm_panel_bridge_add_typed(panel,
> +				DRM_MODE_CONNECTOR_DSI);
> +			if (IS_ERR(bridge))
> +				return PTR_ERR(bridge);
> +		}
> +
> +		priv->output.next_bridge = bridge;
> +		priv->output.panel = panel;
> +	}
> +
> +	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
>  				 flags);
>  }
>  
>
Tomi Valkeinen Aug. 11, 2023, 4:58 p.m. UTC | #2 
On 11/08/2023 19:44, Péter Ujfalusi wrote:
> 
> 
> On 04/08/2023 13:44, Tomi Valkeinen wrote:
> 
> I would rather have a commit message than a blank one.

Oops...

>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
>>   1 file changed, 45 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
>> index ea19de5509ed..a567f136ddc7 100644
>> --- a/drivers/gpu/drm/bridge/tc358768.c
>> +++ b/drivers/gpu/drm/bridge/tc358768.c
>> @@ -131,8 +131,17 @@ static const char * const tc358768_supplies[] = {
>>   
>>   struct tc358768_dsi_output {
>>   	struct mipi_dsi_device *dev;
>> +
>> +	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
>>   	struct drm_panel *panel;
>> -	struct drm_bridge *bridge;
>> +
>> +	/*
>> +	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
>> +	 * to tc358768, 'next_bridge' contains the bridge the driver created
>> +	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
>> +	 * the next bridge the driver found.
>> +	 */
>> +	struct drm_bridge *next_bridge;
> 
> why it is better to call it next_bridge than just bridge? Is there a
> prev_bridge also?

There is, prev bridge would be the bridge behind tc358768 in the chain. 
Bridge is tc358768. Next bridge is the following one.

Here, it's in the tc358768_dsi_output struct, so bridge is perhaps ok. I 
just wanted to be extra clear here, as I think it's often called 
next_bridge in other drivers.

  Tomi
Maxim Schwalm Aug. 13, 2023, 5:11 p.m. UTC | #3 
On 04.08.23 12:44, Tomi Valkeinen wrote:
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
>  1 file changed, 45 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> index ea19de5509ed..a567f136ddc7 100644
> --- a/drivers/gpu/drm/bridge/tc358768.c
> +++ b/drivers/gpu/drm/bridge/tc358768.c
> @@ -131,8 +131,17 @@ static const char * const tc358768_supplies[] = {
>  
>  struct tc358768_dsi_output {
>  	struct mipi_dsi_device *dev;
> +
> +	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
>  	struct drm_panel *panel;
> -	struct drm_bridge *bridge;
> +
> +	/*
> +	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
> +	 * to tc358768, 'next_bridge' contains the bridge the driver created
> +	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
> +	 * the next bridge the driver found.
> +	 */
> +	struct drm_bridge *next_bridge;
>  };
>  
>  struct tc358768_priv {
> @@ -391,8 +400,6 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>  				    struct mipi_dsi_device *dev)
>  {
>  	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
> -	struct drm_bridge *bridge;
> -	struct drm_panel *panel;
>  	struct device_node *ep;
>  	int ret;
>  
> @@ -420,21 +427,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>  		return -ENOTSUPP;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
> -					  &bridge);
> -	if (ret)
> -		return ret;
> -
> -	if (panel) {
> -		bridge = drm_panel_bridge_add_typed(panel,
> -						    DRM_MODE_CONNECTOR_DSI);
> -		if (IS_ERR(bridge))
> -			return PTR_ERR(bridge);
> -	}
> -
>  	priv->output.dev = dev;
> -	priv->output.bridge = bridge;
> -	priv->output.panel = panel;
>  
>  	priv->dsi_lanes = dev->lanes;
>  	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
> @@ -463,7 +456,7 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>  
>  	drm_bridge_remove(&priv->bridge);
>  	if (priv->output.panel)
> -		drm_panel_bridge_remove(priv->output.bridge);
> +		drm_panel_bridge_remove(priv->output.next_bridge);
>  
>  	return 0;
>  }
> @@ -544,7 +537,40 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>  		return -ENOTSUPP;
>  	}
>  
> -	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
> +	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> +		struct device_node *node;
> +
> +		/* Get the next bridge, connected to port@1. */
> +		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
> +		if (!node)
> +			return -ENODEV;
> +
> +		priv->output.next_bridge = of_drm_find_bridge(node);
> +		of_node_put(node);
> +		if (!priv->output.next_bridge)
> +			return -EPROBE_DEFER;
> +	} else {
> +		struct drm_bridge *bridge;
> +		struct drm_panel *panel;
> +		int ret;
> +
> +		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
> +						  &panel, &bridge);
> +		if (ret)
> +			return ret;
> +
> +		if (panel) {
> +			bridge = drm_panel_bridge_add_typed(panel,
> +				DRM_MODE_CONNECTOR_DSI);
> +			if (IS_ERR(bridge))
> +				return PTR_ERR(bridge);
> +		}
> +
> +		priv->output.next_bridge = bridge;
> +		priv->output.panel = panel;
> +	}
> +
> +	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
>  				 flags);
>  }
>  
>
This patch unfortunately breaks the display output on the Asus TF700T:

[drm:drm_bridge_attach] *ERROR* failed to attach bridge /i2c-mux/i2c@1/dsi@7 to encoder LVDS-59: -517
tegra-dc 54200000.dc: failed to initialize RGB output: -517
drm drm: failed to initialize 54200000.dc: -517
------------[ cut here ]------------
WARNING: CPU: 3 PID: 69 at lib/refcount.c:28 tegra_dc_init+0x24/0x5fc
refcount_t: underflow; use-after-free.
Modules linked in: elants_i2c panel_simple tc358768 atkbd vivaldi_fmap
CPU: 3 PID: 69 Comm: kworker/u8:6 Not tainted 6.5.0-rc2-postmarketos-grate #95
Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
Workqueue: events_unbound deferred_probe_work_func
 unwind_backtrace from show_stack+0x10/0x14
 show_stack from dump_stack_lvl+0x40/0x4c
 dump_stack_lvl from __warn+0x94/0xc0
 __warn from warn_slowpath_fmt+0x118/0x16c
 warn_slowpath_fmt from tegra_dc_init+0x24/0x5fc
 tegra_dc_init from host1x_device_init+0x84/0x15c
 host1x_device_init from host1x_drm_probe+0xd8/0x3c4
 host1x_drm_probe from really_probe+0xc8/0x2dc
 really_probe from __driver_probe_device+0x88/0x19c
 __driver_probe_device from driver_probe_device+0x30/0x104
 driver_probe_device from __device_attach_driver+0x94/0x108
 __device_attach_driver from bus_for_each_drv+0x80/0xb8
 bus_for_each_drv from __device_attach+0xa0/0x190
 __device_attach from bus_probe_device+0x88/0x8c
 bus_probe_device from deferred_probe_work_func+0x78/0xa4
 deferred_probe_work_func from process_one_work+0x208/0x420
 process_one_work from worker_thread+0x54/0x550
 worker_thread from kthread+0xdc/0xf8
 kthread from ret_from_fork+0x14/0x2c
Exception stack(0xcf9c5fb0 to 0xcf9c5ff8)
5fa0:                                     00000000 00000000 00000000 00000000
5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 0000000000000000 ]---

Best regards,
Maxim
Tomi Valkeinen Aug. 14, 2023, 7:31 a.m. UTC | #4 
On 13/08/2023 20:11, Maxim Schwalm wrote:
> On 04.08.23 12:44, Tomi Valkeinen wrote:
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
>>   1 file changed, 45 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
>> index ea19de5509ed..a567f136ddc7 100644
>> --- a/drivers/gpu/drm/bridge/tc358768.c
>> +++ b/drivers/gpu/drm/bridge/tc358768.c
>> @@ -131,8 +131,17 @@ static const char * const tc358768_supplies[] = {
>>   
>>   struct tc358768_dsi_output {
>>   	struct mipi_dsi_device *dev;
>> +
>> +	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
>>   	struct drm_panel *panel;
>> -	struct drm_bridge *bridge;
>> +
>> +	/*
>> +	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
>> +	 * to tc358768, 'next_bridge' contains the bridge the driver created
>> +	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
>> +	 * the next bridge the driver found.
>> +	 */
>> +	struct drm_bridge *next_bridge;
>>   };
>>   
>>   struct tc358768_priv {
>> @@ -391,8 +400,6 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>>   				    struct mipi_dsi_device *dev)
>>   {
>>   	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>> -	struct drm_bridge *bridge;
>> -	struct drm_panel *panel;
>>   	struct device_node *ep;
>>   	int ret;
>>   
>> @@ -420,21 +427,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>>   		return -ENOTSUPP;
>>   	}
>>   
>> -	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
>> -					  &bridge);
>> -	if (ret)
>> -		return ret;
>> -
>> -	if (panel) {
>> -		bridge = drm_panel_bridge_add_typed(panel,
>> -						    DRM_MODE_CONNECTOR_DSI);
>> -		if (IS_ERR(bridge))
>> -			return PTR_ERR(bridge);
>> -	}
>> -
>>   	priv->output.dev = dev;
>> -	priv->output.bridge = bridge;
>> -	priv->output.panel = panel;
>>   
>>   	priv->dsi_lanes = dev->lanes;
>>   	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
>> @@ -463,7 +456,7 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>>   
>>   	drm_bridge_remove(&priv->bridge);
>>   	if (priv->output.panel)
>> -		drm_panel_bridge_remove(priv->output.bridge);
>> +		drm_panel_bridge_remove(priv->output.next_bridge);
>>   
>>   	return 0;
>>   }
>> @@ -544,7 +537,40 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>>   		return -ENOTSUPP;
>>   	}
>>   
>> -	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
>> +	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
>> +		struct device_node *node;
>> +
>> +		/* Get the next bridge, connected to port@1. */
>> +		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
>> +		if (!node)
>> +			return -ENODEV;
>> +
>> +		priv->output.next_bridge = of_drm_find_bridge(node);
>> +		of_node_put(node);
>> +		if (!priv->output.next_bridge)
>> +			return -EPROBE_DEFER;
>> +	} else {
>> +		struct drm_bridge *bridge;
>> +		struct drm_panel *panel;
>> +		int ret;
>> +
>> +		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
>> +						  &panel, &bridge);
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (panel) {
>> +			bridge = drm_panel_bridge_add_typed(panel,
>> +				DRM_MODE_CONNECTOR_DSI);
>> +			if (IS_ERR(bridge))
>> +				return PTR_ERR(bridge);
>> +		}
>> +
>> +		priv->output.next_bridge = bridge;
>> +		priv->output.panel = panel;
>> +	}
>> +
>> +	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
>>   				 flags);
>>   }
>>   
>>
> This patch unfortunately breaks the display output on the Asus TF700T:
> 
> [drm:drm_bridge_attach] *ERROR* failed to attach bridge /i2c-mux/i2c@1/dsi@7 to encoder LVDS-59: -517
> tegra-dc 54200000.dc: failed to initialize RGB output: -517
> drm drm: failed to initialize 54200000.dc: -517
> ------------[ cut here ]------------
> WARNING: CPU: 3 PID: 69 at lib/refcount.c:28 tegra_dc_init+0x24/0x5fc
> refcount_t: underflow; use-after-free.
> Modules linked in: elants_i2c panel_simple tc358768 atkbd vivaldi_fmap
> CPU: 3 PID: 69 Comm: kworker/u8:6 Not tainted 6.5.0-rc2-postmarketos-grate #95
> Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
> Workqueue: events_unbound deferred_probe_work_func
>   unwind_backtrace from show_stack+0x10/0x14
>   show_stack from dump_stack_lvl+0x40/0x4c
>   dump_stack_lvl from __warn+0x94/0xc0
>   __warn from warn_slowpath_fmt+0x118/0x16c
>   warn_slowpath_fmt from tegra_dc_init+0x24/0x5fc
>   tegra_dc_init from host1x_device_init+0x84/0x15c
>   host1x_device_init from host1x_drm_probe+0xd8/0x3c4
>   host1x_drm_probe from really_probe+0xc8/0x2dc
>   really_probe from __driver_probe_device+0x88/0x19c
>   __driver_probe_device from driver_probe_device+0x30/0x104
>   driver_probe_device from __device_attach_driver+0x94/0x108
>   __device_attach_driver from bus_for_each_drv+0x80/0xb8
>   bus_for_each_drv from __device_attach+0xa0/0x190
>   __device_attach from bus_probe_device+0x88/0x8c
>   bus_probe_device from deferred_probe_work_func+0x78/0xa4
>   deferred_probe_work_func from process_one_work+0x208/0x420
>   process_one_work from worker_thread+0x54/0x550
>   worker_thread from kthread+0xdc/0xf8
>   kthread from ret_from_fork+0x14/0x2c
> Exception stack(0xcf9c5fb0 to 0xcf9c5ff8)
> 5fa0:                                     00000000 00000000 00000000 00000000
> 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> ---[ end trace 0000000000000000 ]---

Sounds like the Tegra driver has issues cleaning up after getting a 
EPROBE_DEFER.

The tc358768 driver might have an issue with a setup where a panel is 
directly attached to it. I don't have such a setup, but maybe I can fake 
it just to see if the probing goes ok.

  Tomi
Tomi Valkeinen Aug. 14, 2023, 10:04 a.m. UTC | #5 
On 13/08/2023 20:11, Maxim Schwalm wrote:
> On 04.08.23 12:44, Tomi Valkeinen wrote:
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/gpu/drm/bridge/tc358768.c | 64 +++++++++++++++++++++++++++------------
>>   1 file changed, 45 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
>> index ea19de5509ed..a567f136ddc7 100644
>> --- a/drivers/gpu/drm/bridge/tc358768.c
>> +++ b/drivers/gpu/drm/bridge/tc358768.c
>> @@ -131,8 +131,17 @@ static const char * const tc358768_supplies[] = {
>>   
>>   struct tc358768_dsi_output {
>>   	struct mipi_dsi_device *dev;
>> +
>> +	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
>>   	struct drm_panel *panel;
>> -	struct drm_bridge *bridge;
>> +
>> +	/*
>> +	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
>> +	 * to tc358768, 'next_bridge' contains the bridge the driver created
>> +	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
>> +	 * the next bridge the driver found.
>> +	 */
>> +	struct drm_bridge *next_bridge;
>>   };
>>   
>>   struct tc358768_priv {
>> @@ -391,8 +400,6 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>>   				    struct mipi_dsi_device *dev)
>>   {
>>   	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>> -	struct drm_bridge *bridge;
>> -	struct drm_panel *panel;
>>   	struct device_node *ep;
>>   	int ret;
>>   
>> @@ -420,21 +427,7 @@ static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
>>   		return -ENOTSUPP;
>>   	}
>>   
>> -	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
>> -					  &bridge);
>> -	if (ret)
>> -		return ret;
>> -
>> -	if (panel) {
>> -		bridge = drm_panel_bridge_add_typed(panel,
>> -						    DRM_MODE_CONNECTOR_DSI);
>> -		if (IS_ERR(bridge))
>> -			return PTR_ERR(bridge);
>> -	}
>> -
>>   	priv->output.dev = dev;
>> -	priv->output.bridge = bridge;
>> -	priv->output.panel = panel;
>>   
>>   	priv->dsi_lanes = dev->lanes;
>>   	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
>> @@ -463,7 +456,7 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>>   
>>   	drm_bridge_remove(&priv->bridge);
>>   	if (priv->output.panel)
>> -		drm_panel_bridge_remove(priv->output.bridge);
>> +		drm_panel_bridge_remove(priv->output.next_bridge);
>>   
>>   	return 0;
>>   }
>> @@ -544,7 +537,40 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>>   		return -ENOTSUPP;
>>   	}
>>   
>> -	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
>> +	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
>> +		struct device_node *node;
>> +
>> +		/* Get the next bridge, connected to port@1. */
>> +		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
>> +		if (!node)
>> +			return -ENODEV;
>> +
>> +		priv->output.next_bridge = of_drm_find_bridge(node);
>> +		of_node_put(node);
>> +		if (!priv->output.next_bridge)
>> +			return -EPROBE_DEFER;
>> +	} else {
>> +		struct drm_bridge *bridge;
>> +		struct drm_panel *panel;
>> +		int ret;
>> +
>> +		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
>> +						  &panel, &bridge);
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (panel) {
>> +			bridge = drm_panel_bridge_add_typed(panel,
>> +				DRM_MODE_CONNECTOR_DSI);
>> +			if (IS_ERR(bridge))
>> +				return PTR_ERR(bridge);
>> +		}
>> +
>> +		priv->output.next_bridge = bridge;
>> +		priv->output.panel = panel;
>> +	}
>> +
>> +	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
>>   				 flags);
>>   }
>>   
>>
> This patch unfortunately breaks the display output on the Asus TF700T:
> 
> [drm:drm_bridge_attach] *ERROR* failed to attach bridge /i2c-mux/i2c@1/dsi@7 to encoder LVDS-59: -517
> tegra-dc 54200000.dc: failed to initialize RGB output: -517
> drm drm: failed to initialize 54200000.dc: -517
> ------------[ cut here ]------------
> WARNING: CPU: 3 PID: 69 at lib/refcount.c:28 tegra_dc_init+0x24/0x5fc
> refcount_t: underflow; use-after-free.
> Modules linked in: elants_i2c panel_simple tc358768 atkbd vivaldi_fmap
> CPU: 3 PID: 69 Comm: kworker/u8:6 Not tainted 6.5.0-rc2-postmarketos-grate #95
> Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
> Workqueue: events_unbound deferred_probe_work_func
>   unwind_backtrace from show_stack+0x10/0x14
>   show_stack from dump_stack_lvl+0x40/0x4c
>   dump_stack_lvl from __warn+0x94/0xc0
>   __warn from warn_slowpath_fmt+0x118/0x16c
>   warn_slowpath_fmt from tegra_dc_init+0x24/0x5fc
>   tegra_dc_init from host1x_device_init+0x84/0x15c
>   host1x_device_init from host1x_drm_probe+0xd8/0x3c4
>   host1x_drm_probe from really_probe+0xc8/0x2dc
>   really_probe from __driver_probe_device+0x88/0x19c
>   __driver_probe_device from driver_probe_device+0x30/0x104
>   driver_probe_device from __device_attach_driver+0x94/0x108
>   __device_attach_driver from bus_for_each_drv+0x80/0xb8
>   bus_for_each_drv from __device_attach+0xa0/0x190
>   __device_attach from bus_probe_device+0x88/0x8c
>   bus_probe_device from deferred_probe_work_func+0x78/0xa4
>   deferred_probe_work_func from process_one_work+0x208/0x420
>   process_one_work from worker_thread+0x54/0x550
>   worker_thread from kthread+0xdc/0xf8
>   kthread from ret_from_fork+0x14/0x2c
> Exception stack(0xcf9c5fb0 to 0xcf9c5ff8)
> 5fa0:                                     00000000 00000000 00000000 00000000
> 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> ---[ end trace 0000000000000000 ]---

Hi Maxim,

Can you try the attached patch (on top of the series)? If it helps, I'll 
refresh the series with the fix.

  Tomi
Sam Ravnborg Aug. 14, 2023, 10:10 a.m. UTC | #6 
Hi Tomi,

> From c13c691bd8826b978325575be9a87f577b83b86b Mon Sep 17 00:00:00 2001
> From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> Date: Mon, 14 Aug 2023 13:02:23 +0300
> Subject: [PATCH] drm/bridge: tc358768: fix 'Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
>  support'
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/bridge/tc358768.c | 56 +++++++++++++------------------
>  1 file changed, 24 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> index 82ea4d9a814a..9705ce1bd028 100644
> --- a/drivers/gpu/drm/bridge/tc358768.c
> +++ b/drivers/gpu/drm/bridge/tc358768.c
> @@ -455,8 +455,6 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>  	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>  
>  	drm_bridge_remove(&priv->bridge);
> -	if (priv->output.panel)
> -		drm_panel_bridge_remove(priv->output.next_bridge);
>  
>  	return 0;
>  }
> @@ -531,49 +529,42 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>  				  enum drm_bridge_attach_flags flags)
>  {
>  	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
> +	struct drm_bridge *next_bridge;
> +	struct drm_panel *panel;
> +	int ret;
>  
>  	if (!drm_core_check_feature(bridge->dev, DRIVER_ATOMIC)) {
>  		dev_err(priv->dev, "needs atomic updates support\n");
>  		return -ENOTSUPP;
>  	}
>  
> -	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> -		struct device_node *node;
> -
> -		/* Get the next bridge, connected to port@1. */
> -		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
> -		if (!node)
> -			return -ENODEV;
> -
> -		priv->output.next_bridge = of_drm_find_bridge(node);
> -		of_node_put(node);
> -		if (!priv->output.next_bridge)
> -			return -EPROBE_DEFER;
> -	} else {
> -		struct drm_bridge *bridge;
> -		struct drm_panel *panel;
> -		int ret;
> -
> -		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
> -						  &panel, &bridge);
> -		if (ret)
> -			return ret;
> -
> -		if (panel) {
> -			bridge = drm_panel_bridge_add_typed(panel,
> -				DRM_MODE_CONNECTOR_DSI);
> -			if (IS_ERR(bridge))
> -				return PTR_ERR(bridge);
> -		}
> +	ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, -1, &panel,
> +					  &next_bridge);

I think the right way is to wrap the panel in a bridge,
so something like:

	next_bridge = devm_drm_of_get_bridge(dev, priv->dev->of_node, 1, -1)

	if (IS_ERR(next_bridge))
		return ...
	priv->output.next_bridge = next_bridge;


	Sam


> +	if (ret)
> +		return ret;
>  
> -		priv->output.next_bridge = bridge;
> -		priv->output.panel = panel;
> +	if (panel) {
> +		next_bridge = drm_panel_bridge_add_typed(panel,
> +			DRM_MODE_CONNECTOR_DSI);
> +		if (IS_ERR(next_bridge))
> +			return PTR_ERR(next_bridge);
>  	}
>  
> +	priv->output.next_bridge = next_bridge;
> +	priv->output.panel = panel;
> +
>  	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
>  				 flags);
>  }
>  
> +void tc358768_bridge_detach(struct drm_bridge *bridge)
> +{
> +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
> +
> +	if (priv->output.panel)
> +		drm_panel_bridge_remove(priv->output.next_bridge);
> +}
> +
>  static enum drm_mode_status
>  tc358768_bridge_mode_valid(struct drm_bridge *bridge,
>  			   const struct drm_display_info *info,
> @@ -1156,6 +1147,7 @@ tc358768_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>  
>  static const struct drm_bridge_funcs tc358768_bridge_funcs = {
>  	.attach = tc358768_bridge_attach,
> +	.detach = tc358768_bridge_detach,
>  	.mode_valid = tc358768_bridge_mode_valid,
>  	.pre_enable = tc358768_bridge_pre_enable,
>  	.enable = tc358768_bridge_enable,
> -- 
> 2.34.1
>
Laurent Pinchart Aug. 14, 2023, 10:17 a.m. UTC | #7 
On Mon, Aug 14, 2023 at 12:10:41PM +0200, Sam Ravnborg wrote:
> > From c13c691bd8826b978325575be9a87f577b83b86b Mon Sep 17 00:00:00 2001
> > From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> > Date: Mon, 14 Aug 2023 13:02:23 +0300
> > Subject: [PATCH] drm/bridge: tc358768: fix 'Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
> >  support'
> > 
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> > ---
> >  drivers/gpu/drm/bridge/tc358768.c | 56 +++++++++++++------------------
> >  1 file changed, 24 insertions(+), 32 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> > index 82ea4d9a814a..9705ce1bd028 100644
> > --- a/drivers/gpu/drm/bridge/tc358768.c
> > +++ b/drivers/gpu/drm/bridge/tc358768.c
> > @@ -455,8 +455,6 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
> >  	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
> >  
> >  	drm_bridge_remove(&priv->bridge);
> > -	if (priv->output.panel)
> > -		drm_panel_bridge_remove(priv->output.next_bridge);
> >  
> >  	return 0;
> >  }
> > @@ -531,49 +529,42 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
> >  				  enum drm_bridge_attach_flags flags)
> >  {
> >  	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
> > +	struct drm_bridge *next_bridge;
> > +	struct drm_panel *panel;
> > +	int ret;
> >  
> >  	if (!drm_core_check_feature(bridge->dev, DRIVER_ATOMIC)) {
> >  		dev_err(priv->dev, "needs atomic updates support\n");
> >  		return -ENOTSUPP;
> >  	}
> >  
> > -	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> > -		struct device_node *node;
> > -
> > -		/* Get the next bridge, connected to port@1. */
> > -		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
> > -		if (!node)
> > -			return -ENODEV;
> > -
> > -		priv->output.next_bridge = of_drm_find_bridge(node);
> > -		of_node_put(node);
> > -		if (!priv->output.next_bridge)
> > -			return -EPROBE_DEFER;
> > -	} else {
> > -		struct drm_bridge *bridge;
> > -		struct drm_panel *panel;
> > -		int ret;
> > -
> > -		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
> > -						  &panel, &bridge);
> > -		if (ret)
> > -			return ret;
> > -
> > -		if (panel) {
> > -			bridge = drm_panel_bridge_add_typed(panel,
> > -				DRM_MODE_CONNECTOR_DSI);
> > -			if (IS_ERR(bridge))
> > -				return PTR_ERR(bridge);
> > -		}
> > +	ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, -1, &panel,
> > +					  &next_bridge);
> 
> I think the right way is to wrap the panel in a bridge,
> so something like:
> 
> 	next_bridge = devm_drm_of_get_bridge(dev, priv->dev->of_node, 1, -1)
> 
> 	if (IS_ERR(next_bridge))
> 		return ...
> 	priv->output.next_bridge = next_bridge;

Should we at some point bite the bullet and wrap panels in bridges
directly in drm_panel.c ? That would simplify all the consumers.

> > +	if (ret)
> > +		return ret;
> >  
> > -		priv->output.next_bridge = bridge;
> > -		priv->output.panel = panel;
> > +	if (panel) {
> > +		next_bridge = drm_panel_bridge_add_typed(panel,
> > +			DRM_MODE_CONNECTOR_DSI);
> > +		if (IS_ERR(next_bridge))
> > +			return PTR_ERR(next_bridge);
> >  	}
> >  
> > +	priv->output.next_bridge = next_bridge;
> > +	priv->output.panel = panel;
> > +
> >  	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
> >  				 flags);
> >  }
> >  
> > +void tc358768_bridge_detach(struct drm_bridge *bridge)
> > +{
> > +	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
> > +
> > +	if (priv->output.panel)
> > +		drm_panel_bridge_remove(priv->output.next_bridge);
> > +}
> > +
> >  static enum drm_mode_status
> >  tc358768_bridge_mode_valid(struct drm_bridge *bridge,
> >  			   const struct drm_display_info *info,
> > @@ -1156,6 +1147,7 @@ tc358768_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> >  
> >  static const struct drm_bridge_funcs tc358768_bridge_funcs = {
> >  	.attach = tc358768_bridge_attach,
> > +	.detach = tc358768_bridge_detach,
> >  	.mode_valid = tc358768_bridge_mode_valid,
> >  	.pre_enable = tc358768_bridge_pre_enable,
> >  	.enable = tc358768_bridge_enable,
Tomi Valkeinen Aug. 14, 2023, 1:29 p.m. UTC | #8 
Hi Sam,

On 14/08/2023 13:10, Sam Ravnborg wrote:
> Hi Tomi,
> 
>>  From c13c691bd8826b978325575be9a87f577b83b86b Mon Sep 17 00:00:00 2001
>> From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> Date: Mon, 14 Aug 2023 13:02:23 +0300
>> Subject: [PATCH] drm/bridge: tc358768: fix 'Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
>>   support'
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/gpu/drm/bridge/tc358768.c | 56 +++++++++++++------------------
>>   1 file changed, 24 insertions(+), 32 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
>> index 82ea4d9a814a..9705ce1bd028 100644
>> --- a/drivers/gpu/drm/bridge/tc358768.c
>> +++ b/drivers/gpu/drm/bridge/tc358768.c
>> @@ -455,8 +455,6 @@ static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
>>   	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
>>   
>>   	drm_bridge_remove(&priv->bridge);
>> -	if (priv->output.panel)
>> -		drm_panel_bridge_remove(priv->output.next_bridge);
>>   
>>   	return 0;
>>   }
>> @@ -531,49 +529,42 @@ static int tc358768_bridge_attach(struct drm_bridge *bridge,
>>   				  enum drm_bridge_attach_flags flags)
>>   {
>>   	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
>> +	struct drm_bridge *next_bridge;
>> +	struct drm_panel *panel;
>> +	int ret;
>>   
>>   	if (!drm_core_check_feature(bridge->dev, DRIVER_ATOMIC)) {
>>   		dev_err(priv->dev, "needs atomic updates support\n");
>>   		return -ENOTSUPP;
>>   	}
>>   
>> -	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
>> -		struct device_node *node;
>> -
>> -		/* Get the next bridge, connected to port@1. */
>> -		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
>> -		if (!node)
>> -			return -ENODEV;
>> -
>> -		priv->output.next_bridge = of_drm_find_bridge(node);
>> -		of_node_put(node);
>> -		if (!priv->output.next_bridge)
>> -			return -EPROBE_DEFER;
>> -	} else {
>> -		struct drm_bridge *bridge;
>> -		struct drm_panel *panel;
>> -		int ret;
>> -
>> -		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
>> -						  &panel, &bridge);
>> -		if (ret)
>> -			return ret;
>> -
>> -		if (panel) {
>> -			bridge = drm_panel_bridge_add_typed(panel,
>> -				DRM_MODE_CONNECTOR_DSI);
>> -			if (IS_ERR(bridge))
>> -				return PTR_ERR(bridge);
>> -		}
>> +	ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, -1, &panel,
>> +					  &next_bridge);
> 
> I think the right way is to wrap the panel in a bridge,
> so something like:
> 
> 	next_bridge = devm_drm_of_get_bridge(dev, priv->dev->of_node, 1, -1)
> 
> 	if (IS_ERR(next_bridge))
> 		return ...
> 	priv->output.next_bridge = next_bridge;

I tried that, but I had trouble with the cleanup side.

In the fixup patch I attached in my reply to Maxim I used 
drm_of_find_panel_or_bridge() + drm_panel_bridge_add_typed(), and on 
bridge_detach callback I used drm_panel_bridge_remove() (if there is a 
panel). This worked for me, but it does feel like a bit too much work 
for a driver to do.

  Tomi
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index ea19de5509ed..a567f136ddc7 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -131,8 +131,17 @@  static const char * const tc358768_supplies[] = {
 
 struct tc358768_dsi_output {
 	struct mipi_dsi_device *dev;
+
+	/* Legacy field if DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used */
 	struct drm_panel *panel;
-	struct drm_bridge *bridge;
+
+	/*
+	 * If DRM_BRIDGE_ATTACH_NO_CONNECTOR is not used and a panel is attached
+	 * to tc358768, 'next_bridge' contains the bridge the driver created
+	 * with drm_panel_bridge_add_typed(). Otherwise 'next_bridge' contains
+	 * the next bridge the driver found.
+	 */
+	struct drm_bridge *next_bridge;
 };
 
 struct tc358768_priv {
@@ -391,8 +400,6 @@  static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
 				    struct mipi_dsi_device *dev)
 {
 	struct tc358768_priv *priv = dsi_host_to_tc358768(host);
-	struct drm_bridge *bridge;
-	struct drm_panel *panel;
 	struct device_node *ep;
 	int ret;
 
@@ -420,21 +427,7 @@  static int tc358768_dsi_host_attach(struct mipi_dsi_host *host,
 		return -ENOTSUPP;
 	}
 
-	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
-					  &bridge);
-	if (ret)
-		return ret;
-
-	if (panel) {
-		bridge = drm_panel_bridge_add_typed(panel,
-						    DRM_MODE_CONNECTOR_DSI);
-		if (IS_ERR(bridge))
-			return PTR_ERR(bridge);
-	}
-
 	priv->output.dev = dev;
-	priv->output.bridge = bridge;
-	priv->output.panel = panel;
 
 	priv->dsi_lanes = dev->lanes;
 	priv->dsi_bpp = mipi_dsi_pixel_format_to_bpp(dev->format);
@@ -463,7 +456,7 @@  static int tc358768_dsi_host_detach(struct mipi_dsi_host *host,
 
 	drm_bridge_remove(&priv->bridge);
 	if (priv->output.panel)
-		drm_panel_bridge_remove(priv->output.bridge);
+		drm_panel_bridge_remove(priv->output.next_bridge);
 
 	return 0;
 }
@@ -544,7 +537,40 @@  static int tc358768_bridge_attach(struct drm_bridge *bridge,
 		return -ENOTSUPP;
 	}
 
-	return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
+	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+		struct device_node *node;
+
+		/* Get the next bridge, connected to port@1. */
+		node = of_graph_get_remote_node(priv->dev->of_node, 1, -1);
+		if (!node)
+			return -ENODEV;
+
+		priv->output.next_bridge = of_drm_find_bridge(node);
+		of_node_put(node);
+		if (!priv->output.next_bridge)
+			return -EPROBE_DEFER;
+	} else {
+		struct drm_bridge *bridge;
+		struct drm_panel *panel;
+		int ret;
+
+		ret = drm_of_find_panel_or_bridge(priv->dev->of_node, 1, 0,
+						  &panel, &bridge);
+		if (ret)
+			return ret;
+
+		if (panel) {
+			bridge = drm_panel_bridge_add_typed(panel,
+				DRM_MODE_CONNECTOR_DSI);
+			if (IS_ERR(bridge))
+				return PTR_ERR(bridge);
+		}
+
+		priv->output.next_bridge = bridge;
+		priv->output.panel = panel;
+	}
+
+	return drm_bridge_attach(bridge->encoder, priv->output.next_bridge, bridge,
 				 flags);
 }