Commit ee5c2c7d authored by Louis Chauvet's avatar Louis Chauvet Committed by Luca Ceresoli
Browse files

drm/vkms: Allow to configure CRTC writeback support via configfs 



When a CRTC is created, add a `writeback` file to allow to enable or
disable writeback connector support

Tested-by: default avatarMark Yacoub <markyacoub@google.com>
Reviewed-by: default avatarLouis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
Reviewed-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: default avatarLouis Chauvet <louis.chauvet@bootlin.com>
Co-developed-by: default avatarJosé Expósito <jose.exposito89@gmail.com>
Signed-off-by: default avatarJosé Expósito <jose.exposito89@gmail.com>
Link: https://lore.kernel.org/r/20251016175618.10051-7-jose.exposito89@gmail.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent 3e4d5b30

Documentation/gpu/vkms.rst

+4 −0
Original line number Diff line number Diff line
@@ -94,6 +94,10 @@ Continue by creating one or more CRTCs:: 


  sudo mkdir /config/vkms/my-vkms/crtcs/crtc0



CRTCs have 1 configurable attribute:



- writeback: Enable or disable writeback connector support by writing 1 or 0



Once you are done configuring the VKMS instance, enable it::



  echo "1" | sudo tee /config/vkms/my-vkms/enabled

drivers/gpu/drm/vkms/vkms_configfs.c

+42 −0
Original line number Diff line number Diff line
@@ -74,6 +74,47 @@ struct vkms_configfs_crtc { 
#define crtc_item_to_vkms_configfs_crtc(item) \

	container_of(to_config_group((item)), struct vkms_configfs_crtc, group)



static ssize_t crtc_writeback_show(struct config_item *item, char *page)

{

	struct vkms_configfs_crtc *crtc;

	bool writeback;



	crtc = crtc_item_to_vkms_configfs_crtc(item);



	scoped_guard(mutex, &crtc->dev->lock)

		writeback = vkms_config_crtc_get_writeback(crtc->config);



	return sprintf(page, "%d\n", writeback);

}



static ssize_t crtc_writeback_store(struct config_item *item, const char *page,

				    size_t count)

{

	struct vkms_configfs_crtc *crtc;

	bool writeback;



	crtc = crtc_item_to_vkms_configfs_crtc(item);



	if (kstrtobool(page, &writeback))

		return -EINVAL;



	scoped_guard(mutex, &crtc->dev->lock) {

		if (crtc->dev->enabled)

			return -EBUSY;



		vkms_config_crtc_set_writeback(crtc->config, writeback);

	}



	return (ssize_t)count;

}



CONFIGFS_ATTR(crtc_, writeback);



static struct configfs_attribute *crtc_item_attrs[] = {

	&crtc_attr_writeback,

	NULL,

};



static void crtc_release(struct config_item *item)

{

	struct vkms_configfs_crtc *crtc;
@@ -93,6 +134,7 @@ static struct configfs_item_operations crtc_item_operations = { 
};



static const struct config_item_type crtc_item_type = {

	.ct_attrs	= crtc_item_attrs,

	.ct_item_ops	= &crtc_item_operations,

	.ct_owner	= THIS_MODULE,

};