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Commit c10802b6 authored by Peter Wu's avatar Peter Wu Committed by Gerd Hoffmann
Browse files

drm/fb-helper: improve documentation and print warnings 



Clarify the relation between drm_fb_helper_fbdev_setup/teardown. Clarify
requirements for the new generic fbdev emulation API and log some more
details in case the driver does something wrong. Fix related typos.

Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: default avatarPeter Wu <peter@lekensteyn.nl>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180906221810.20170-5-peter@lekensteyn.nl


Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent 7780eb9c

drivers/gpu/drm/drm_fb_helper.c

+18 −6
Original line number Diff line number Diff line
@@ -2821,7 +2821,9 @@ EXPORT_SYMBOL(drm_fb_helper_hotplug_event); 
 * The caller must to provide a &drm_fb_helper_funcs->fb_probe callback

 * function.

 *

 * See also: drm_fb_helper_initial_config()

 * Use drm_fb_helper_fbdev_teardown() to destroy the fbdev.

 *

 * See also: drm_fb_helper_initial_config(), drm_fbdev_generic_setup().

 *

 * Returns:

 * Zero on success or negative error code on failure.
@@ -3037,7 +3039,7 @@ static struct fb_deferred_io drm_fbdev_defio = { 
 * @fb_helper: fbdev helper structure

 * @sizes: describes fbdev size and scanout surface size

 *

 * This function uses the client API to crate a framebuffer backed by a dumb buffer.

 * This function uses the client API to create a framebuffer backed by a dumb buffer.

 *

 * The _sys_ versions are used for &fb_ops.fb_read, fb_write, fb_fillrect,

 * fb_copyarea, fb_imageblit.
@@ -3165,8 +3167,10 @@ static int drm_fbdev_client_hotplug(struct drm_client_dev *client) 
	if (dev->fb_helper)

		return drm_fb_helper_hotplug_event(dev->fb_helper);



	if (!dev->mode_config.num_connector)

	if (!dev->mode_config.num_connector) {

		DRM_DEV_DEBUG(dev->dev, "No connectors found, will not create framebuffer!\n");

		return 0;

	}



	ret = drm_fb_helper_fbdev_setup(dev, fb_helper, &drm_fb_helper_generic_funcs,

					fb_helper->preferred_bpp, 0);
@@ -3187,13 +3191,14 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = { 
};



/**

 * drm_fb_helper_generic_fbdev_setup() - Setup generic fbdev emulation

 * drm_fbdev_generic_setup() - Setup generic fbdev emulation

 * @dev: DRM device

 * @preferred_bpp: Preferred bits per pixel for the device.

 *                 @dev->mode_config.preferred_depth is used if this is zero.

 *

 * This function sets up generic fbdev emulation for drivers that supports

 * dumb buffers with a virtual address and that can be mmap'ed.

 * dumb buffers with a virtual address and that can be mmap'ed. If the driver

 * does not support these functions, it could use drm_fb_helper_fbdev_setup().

 *

 * Restore, hotplug events and teardown are all taken care of. Drivers that do

 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
@@ -3206,6 +3211,8 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = { 
 * This function is safe to call even when there are no connectors present.

 * Setup will be retried on the next hotplug event.

 *

 * The fbdev is destroyed by drm_dev_unregister().

 *

 * Returns:

 * Zero on success or negative error code on failure.

 */
@@ -3214,6 +3221,8 @@ int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) 
	struct drm_fb_helper *fb_helper;

	int ret;



	WARN(dev->fb_helper, "fb_helper is already set!\n");



	if (!drm_fbdev_emulation)

		return 0;
@@ -3224,12 +3233,15 @@ int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) 
	ret = drm_client_new(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);

	if (ret) {

		kfree(fb_helper);

		DRM_DEV_ERROR(dev->dev, "Failed to register client: %d\n", ret);

		return ret;

	}



	fb_helper->preferred_bpp = preferred_bpp;



	drm_fbdev_client_hotplug(&fb_helper->client);

	ret = drm_fbdev_client_hotplug(&fb_helper->client);

	if (ret)

		DRM_DEV_DEBUG(dev->dev, "client hotplug ret=%d\n", ret);



	return 0;

}