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drm/fb-helper: Update DOC with new helpers 

Promote new helpers for dealing with fbdev emulation.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171215175119.36181-5-noralf@tronnes.org
hifive-unleashed-5.1
Noralf Trønnes 2017-12-15 18:51:16 +01:00
parent ee05baa0bf
commit 95b0137f28
1 changed files with 16 additions and 12 deletions
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28
drivers/gpu/drm/drm_fb_helper.c
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@ -66,19 +66,23 @@ static DEFINE_MUTEX(kernel_fb_helper_lock);
* helper functions used by many drivers to implement the kernel mode setting
* interfaces.
*
* Initialization is done as a four-step process with drm_fb_helper_prepare(),
* drm_fb_helper_init(), drm_fb_helper_single_add_all_connectors() and
* drm_fb_helper_initial_config(). Drivers with fancier requirements than the
* default behaviour can override the third step with their own code.
* Teardown is done with drm_fb_helper_fini() after the fbdev device is
* unregisters using drm_fb_helper_unregister_fbi().
* Setup fbdev emulation by calling drm_fb_helper_fbdev_setup() and tear it
* down by calling drm_fb_helper_fbdev_teardown().
*
* At runtime drivers should restore the fbdev console by calling
* drm_fb_helper_restore_fbdev_mode_unlocked() from their &drm_driver.lastclose
* callback. They should also notify the fb helper code from updates to the
* output configuration by calling drm_fb_helper_hotplug_event(). For easier
* integration with the output polling code in drm_crtc_helper.c the modeset
* code provides a &drm_mode_config_funcs.output_poll_changed callback.
* Drivers that need to handle connector hotplugging (e.g. dp mst) can't use
* the setup helper and will need to do the whole four-step setup process with
* drm_fb_helper_prepare(), drm_fb_helper_init(),
* drm_fb_helper_single_add_all_connectors(), enable hotplugging and
* drm_fb_helper_initial_config() to avoid a possible race window.
*
* At runtime drivers should restore the fbdev console by using
* drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
* They should also notify the fb helper code from updates to the output
* configuration by using drm_fb_helper_output_poll_changed() as their
* &drm_mode_config_funcs.output_poll_changed callback.
*
* For suspend/resume consider using drm_mode_config_helper_suspend() and
* drm_mode_config_helper_resume() which takes care of fbdev as well.
*
* All other functions exported by the fb helper library can be used to
* implement the fbdev driver interface by the driver.