[PATCH v2 4/7] drm/fb-helper: Update DOC with new helpers
Noralf Trønnes
noralf at tronnes.org
Fri Dec 15 17:51:16 UTC 2017
Promote new helpers for dealing with fbdev emulation.
Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/gpu/drm/drm_fb_helper.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 823fc8f50d85..e3eb3c9a98e3 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -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.
--
2.14.2
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