Re: [PATCH v5 02/24] drm: Add drm_connector_init() variant with ddc

Re: [PATCH v5 02/24] drm: Add drm_connector_init() variant with ddc

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 2603 bytes --]

Hi

Am 24.07.19 um 15:59 schrieb Andrzej Pietrasiewicz:
> Allow passing ddc adapter pointer to the init function. Even if
> drm_connector_init() sometime in the future decides to e.g. memset() all
> connector fields to zeros, the newly added function ensures that at its
> completion the ddc member of connector is correctly set.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 19 +++++++++++++++++++
>  include/drm/drm_connector.h     |  5 +++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 068d4b05f1be..06fbfc44fb48 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -296,6 +296,25 @@ int drm_connector_init(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_connector_init);
>  
> +int drm_connector_init_with_ddc(struct drm_device *dev,
> +				struct drm_connector *connector,
> +				const struct drm_connector_funcs *funcs,
> +				int connector_type,
> +				struct i2c_adapter *ddc)
> +{
> +	int ret;
> +
> +	ret = drm_connector_init(dev, connector, funcs, connector_type);
> +	if (ret)
> +		return ret;
> +
> +	/* provide ddc symlink in sysfs */
> +	connector->ddc = ddc;
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_connector_init_with_ddc);
> +

Thanks for including such a function.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

>  /**
>   * drm_connector_attach_edid_property - attach edid property.
>   * @connector: the connector
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 33a6fff85fdb..937fda9c1374 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1410,6 +1410,11 @@ int drm_connector_init(struct drm_device *dev,
>  		       struct drm_connector *connector,
>  		       const struct drm_connector_funcs *funcs,
>  		       int connector_type);
> +int drm_connector_init_with_ddc(struct drm_device *dev,
> +				struct drm_connector *connector,
> +				const struct drm_connector_funcs *funcs,
> +				int connector_type,
> +				struct i2c_adapter *ddc);
>  void drm_connector_attach_edid_property(struct drm_connector *connector);
>  int drm_connector_register(struct drm_connector *connector);
>  void drm_connector_unregister(struct drm_connector *connector);
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v5 18/24] drm/ast: Provide ddc symlink in connector sysfs directory

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 1766 bytes --]



Am 24.07.19 um 15:59 schrieb Andrzej Pietrasiewicz:
> Use the ddc pointer provided by the generic connector.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>  drivers/gpu/drm/ast/ast_mode.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index c792362024a5..1c899a6e87b7 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -867,7 +867,14 @@ static int ast_connector_init(struct drm_device *dev)
>  		return -ENOMEM;
>  
>  	connector = &ast_connector->base;
> -	drm_connector_init(dev, connector, &ast_connector_funcs, DRM_MODE_CONNECTOR_VGA);
> +	ast_connector->i2c = ast_i2c_create(dev);
> +	if (!ast_connector->i2c)
> +		DRM_ERROR("failed to add ddc bus for connector\n");
> +
> +	drm_connector_init_with_ddc(dev, connector,
> +				    &ast_connector_funcs,
> +				    DRM_MODE_CONNECTOR_VGA,
> +				    &ast_connector->i2c->adapter);
>  
>  	drm_connector_helper_add(connector, &ast_connector_helper_funcs);
>  
> @@ -881,10 +888,6 @@ static int ast_connector_init(struct drm_device *dev)
>  	encoder = list_first_entry(&dev->mode_config.encoder_list, struct drm_encoder, head);
>  	drm_connector_attach_encoder(connector, encoder);
>  
> -	ast_connector->i2c = ast_i2c_create(dev);
> -	if (!ast_connector->i2c)
> -		DRM_ERROR("failed to add ddc bus for connector\n");
> -
>  	return 0;
>  }
>  
> 

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v5 01/24] drm: Include ddc adapter pointer in struct drm_connector

[Sam Ravnborg]

Hi Andrzej.

After reading through the series a few more comments.

1) The subject of this patch could be improved.
   Consider something like:
   drm: add ddc link in sysfs created by drm_connector

   This spells out much better what the patch achieve.


2) The purpsoe of drm_connector.ddc is to provide drm_connector with
   info to create the symlink.
   Yet in many follow-up patches the drivers are changed so
   drm_connector.ddc is their only reference to struct i2c_adapter.

   But the ownership is not clear here.
   Who owns the reference to i2c_adapter - and who has the
   responsibility to call put() on the adapter.

   Looking at the conversions done then some drivers are converted
   so they only use drm_connector.ddc, and other drivers have their own
   reference to i2c_adapter.
   The latter looks like the correct solution as the ownership of the
   reference belongs to the driver and not drm_connector.

   In other words - a conversion where the drivers only assigned
   drm_connector.ddc (using drm_connector_init_with_ddc()),
   seems like a more clean design that does not mix up ownership.
   This is at least how I see it.
   I did not take this type of look at the patches before. Sorry
   for providing feedback this late.

	Sam

On Fri, Jul 26, 2019 at 08:37:59AM +0200, Sam Ravnborg wrote:
> Hi Andrzej.
> 
> Patch looks good, but one kernel-doc detail.
> 
> On Wed, Jul 24, 2019 at 03:59:23PM +0200, Andrzej Pietrasiewicz wrote:
> > Add generic code which creates symbolic links in sysfs, pointing to ddc
> > interface used by a particular video output. For example:
> > 
> > ls -l /sys/class/drm/card0-HDMI-A-1/ddc
> > lrwxrwxrwx 1 root root 0 Jun 24 10:42 /sys/class/drm/card0-HDMI-A-1/ddc \
> > 	-> ../../../../soc/13880000.i2c/i2c-2
> > 
> > This makes it easy for user to associate a display with its ddc adapter
> > and use e.g. ddcutil to control the chosen monitor.
> > 
> > This patch adds an i2c_adapter pointer to struct drm_connector. Particular
> > drivers can then use it instead of using their own private instance. If a
> > connector contains a ddc, then create a symbolic link in sysfs.
> > 
> > Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> > Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
> > ---
> >  drivers/gpu/drm/drm_sysfs.c |  8 ++++++++
> >  include/drm/drm_connector.h | 11 +++++++++++
> >  2 files changed, 19 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> > index ad10810bc972..e962a9d45f7e 100644
> > --- a/drivers/gpu/drm/drm_sysfs.c
> > +++ b/drivers/gpu/drm/drm_sysfs.c
> > @@ -14,6 +14,7 @@
> >  #include <linux/err.h>
> >  #include <linux/export.h>
> >  #include <linux/gfp.h>
> > +#include <linux/i2c.h>
> >  #include <linux/kdev_t.h>
> >  #include <linux/slab.h>
> >  
> > @@ -294,6 +295,9 @@ int drm_sysfs_connector_add(struct drm_connector *connector)
> >  	/* Let userspace know we have a new connector */
> >  	drm_sysfs_hotplug_event(dev);
> >  
> > +	if (connector->ddc)
> > +		return sysfs_create_link(&connector->kdev->kobj,
> > +				 &connector->ddc->dev.kobj, "ddc");
> >  	return 0;
> >  }
> >  
> > @@ -301,6 +305,10 @@ void drm_sysfs_connector_remove(struct drm_connector *connector)
> >  {
> >  	if (!connector->kdev)
> >  		return;
> > +
> > +	if (connector->ddc)
> > +		sysfs_remove_link(&connector->kdev->kobj, "ddc");
> > +
> >  	DRM_DEBUG("removing \"%s\" from sysfs\n",
> >  		  connector->name);
> >  
> > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > index 4c30d751487a..33a6fff85fdb 100644
> > --- a/include/drm/drm_connector.h
> > +++ b/include/drm/drm_connector.h
> > @@ -41,6 +41,7 @@ struct drm_property;
> >  struct drm_property_blob;
> >  struct drm_printer;
> >  struct edid;
> > +struct i2c_adapter;
> >  
> >  enum drm_connector_force {
> >  	DRM_FORCE_UNSPECIFIED,
> > @@ -1311,6 +1312,16 @@ struct drm_connector {
> >  	 * [0]: progressive, [1]: interlaced
> >  	 */
> >  	int audio_latency[2];
> > +
> > +	/**
> > +	 * @ddc: associated ddc adapter.
> > +	 * A connector usually has its associated ddc adapter. If a driver uses
> > +	 * this field, then an appropriate symbolic link is created in connector
> > +	 * sysfs directory to make it easy for the user to tell which i2c
> > +	 * adapter is for a particular display.
> > +	 */
> > +	struct i2c_adapter *ddc;
> 
> To help the reader could you add in the above a reference to
> drm_connector_init_with_ddc() sp the reader is told how to init this
> field.
> 
> Either add it in PATCH 2 - or merge patch 1 and 2.
> 
> 	Sam
> 
> > +
> >  	/**
> >  	 * @null_edid_counter: track sinks that give us all zeros for the EDID.
> >  	 * Needed to workaround some HW bugs where we get all 0s
> > -- 
> > 2.17.1
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v5 01/24] drm: Include ddc adapter pointer in struct drm_connector

[Andrzej Pietrasiewicz]

Hi Sam,

W dniu 26.07.2019 o 08:37, Sam Ravnborg pisze:
> Hi Andrzej.
> 
> Patch looks good, but one kernel-doc detail.
> 

Thanks, I will address both issues you found, in v6.

Andrzej

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel