diff options
| -rw-r--r-- | include/drm/drm_fb_helper.h | 96 |
1 files changed, 81 insertions, 15 deletions
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index 87b090c..d2d4ad1 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -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; /** |