drm: Polish fbdev helper struct docs

Mostly this is just adding extensive docs for the callbacks, but also
a few other additions.

v2: Use FIXME comments to annotate helper hooks that should be
replaced.

v3: Small nits (Thierry).

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449218769-16577-2-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Daniel Vetter 2015-12-04 09:45:42 +01:00
parent e876b41ab0
commit 264d6970e1

View File

@ -74,25 +74,76 @@ struct drm_fb_helper_surface_size {
/**
* struct drm_fb_helper_funcs - driver callbacks for the fbdev emulation library
* @gamma_set: Set the given gamma lut register on the given crtc.
* @gamma_get: Read the given gamma lut register on the given crtc, used to
* save the current lut when force-restoring the fbdev for e.g.
* kdbg.
* @fb_probe: Driver callback to allocate and initialize the fbdev info
* structure. Furthermore it also needs to allocate the drm
* framebuffer used to back the fbdev.
* @initial_config: Setup an initial fbdev display configuration
*
* Driver callbacks used by the fbdev emulation helper library.
*/
struct drm_fb_helper_funcs {
/**
* @gamma_set:
*
* Set the given gamma LUT register on the given CRTC.
*
* This callback is optional.
*
* FIXME:
*
* This callback is functionally redundant with the core gamma table
* support and simply exists because the fbdev hasn't yet been
* refactored to use the core gamma table interfaces.
*/
void (*gamma_set)(struct drm_crtc *crtc, u16 red, u16 green,
u16 blue, int regno);
/**
* @gamma_get:
*
* Read the given gamma LUT register on the given CRTC, used to save the
* current LUT when force-restoring the fbdev for e.g. kdbg.
*
* This callback is optional.
*
* FIXME:
*
* This callback is functionally redundant with the core gamma table
* support and simply exists because the fbdev hasn't yet been
* refactored to use the core gamma table interfaces.
*/
void (*gamma_get)(struct drm_crtc *crtc, u16 *red, u16 *green,
u16 *blue, int regno);
/**
* @fb_probe:
*
* Driver callback to allocate and initialize the fbdev info structure.
* Furthermore it also needs to allocate the DRM framebuffer used to
* back the fbdev.
*
* This callback is mandatory.
*
* RETURNS:
*
* The driver should return 0 on success and a negative error code on
* failure.
*/
int (*fb_probe)(struct drm_fb_helper *helper,
struct drm_fb_helper_surface_size *sizes);
/**
* @initial_config:
*
* Driver callback to setup an initial fbdev display configuration.
* Drivers can use this callback to tell the fbdev emulation what the
* preferred initial configuration is. This is useful to implement
* smooth booting where the fbdev (and subsequently all userspace) never
* changes the mode, but always inherits the existing configuration.
*
* This callback is optional.
*
* RETURNS:
*
* The driver should return true if a suitable initial configuration has
* been filled out and false when the fbdev helper should fall back to
* the default probing logic.
*/
bool (*initial_config)(struct drm_fb_helper *fb_helper,
struct drm_fb_helper_crtc **crtcs,
struct drm_display_mode **modes,
@ -105,18 +156,22 @@ struct drm_fb_helper_connector {
};
/**
* struct drm_fb_helper - helper to emulate fbdev on top of kms
* @fb: Scanout framebuffer object
* @dev: DRM device
* struct drm_fb_helper - main structure to emulate fbdev on top of KMS
* @fb: Scanout framebuffer object
* @dev: DRM device
* @crtc_count: number of possible CRTCs
* @crtc_info: per-CRTC helper state (mode, x/y offset, etc)
* @connector_count: number of connected connectors
* @connector_info_alloc_count: size of connector_info
* @connector_info: array of per-connector information
* @funcs: driver callbacks for fb helper
* @fbdev: emulated fbdev device info struct
* @pseudo_palette: fake palette of 16 colors
* @kernel_fb_list: list_head in kernel_fb_helper_list
* @delayed_hotplug: was there a hotplug while kms master active?
*
* This is the main structure used by the fbdev helpers. Drivers supporting
* fbdev emulation should embedded this into their overall driver structure.
* Drivers must also fill out a struct &drm_fb_helper_funcs with a few
* operations.
*/
struct drm_fb_helper {
struct drm_framebuffer *fb;
@ -129,10 +184,21 @@ struct drm_fb_helper {
const struct drm_fb_helper_funcs *funcs;
struct fb_info *fbdev;
u32 pseudo_palette[17];
/**
* @kernel_fb_list:
*
* Entry on the global kernel_fb_helper_list, used for kgdb entry/exit.
*/
struct list_head kernel_fb_list;
/* we got a hotplug but fbdev wasn't running the console
delay until next set_par */
/**
* @delayed_hotplug:
*
* A hotplug was received while fbdev wasn't in control of the DRM
* device, i.e. another KMS master was active. The output configuration
* needs to be reprobe when fbdev is in control again.
*/
bool delayed_hotplug;
/**