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Commit 5dec293b authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Daniel Vetter
Browse files

drm: Expand the drm_helper_probe_single_connector_modes() docs 



Describe the procedure that drm_helper_probe_single_connector_modes()
uses to do it's work in the kernel-doc comment.

Caveat: Looks like crap and trying to reverse engineer the documentation
tools is not something I want to do.

Suggested-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449782037-19722-3-git-send-email-ville.syrjala@linux.intel.com
parent 0e8578c9

drivers/gpu/drm/drm_probe_helper.c

+37 −12
Original line number Diff line number Diff line
@@ -144,18 +144,43 @@ EXPORT_SYMBOL(drm_kms_helper_poll_enable_locked); 
 * @connector vfunc for drivers that use the CRTC helpers for output mode

 * filtering and detection.

 *

 * If the helper operation returns no mode, and if the connector status is

 * connector_status_connected, standard VESA DMT modes up to 1024x768 are

 * automatically added to the modes list by a call to

 * drm_add_modes_noedid().

 *

 * The function then filters out modes larger than @maxX and maxY if specified.

 * It finally calls the optional connector ->mode_valid() helper operation for each

 * mode in the probed list to check whether the mode is valid for the connector.

 *

 * Compared to drm_helper_probe_single_connector_modes_nomerge() this function

 * merged the mode bits for the preferred mode, as a hack to work around some

 * quirky issues on funky hardware.

 * The basic procedure is as follows

 *

 * 1. All modes currently on the connector's modes list are marked as stale

 *

 * 2. New modes are added to the connector's probed_modes list with

 *    drm_mode_probed_add(). New modes start their life with status as OK.

 *    Modes are added from a single source using the following priority order.

 *

 *    - debugfs 'override_edid' (used for testing only)

 *    - firmware EDID (drm_load_edid_firmware())

 *    - connector helper ->get_modes() vfunc

 *    - if the connector status is connector_status_connected, standard

 *      VESA DMT modes up to 1024x768 are automatically added

 *      (drm_add_modes_noedid())

 *

 *    Finally modes specified via the kernel command line (video=...) are

 *    added in addition to what the earlier probes produced

 *    (drm_helper_probe_add_cmdline_mode()). These modes are generated

 *    using the VESA GTF/CVT formulas.

 *

 * 3. Modes are moved from the probed_modes list to the modes list. Potential

 *    duplicates are merged together (see drm_mode_connector_list_update()).

 *    After this step the probed_modes list will be empty again.

 *

 * 4. Any non-stale mode on the modes list then undergoes validation

 *

 *    - drm_mode_validate_basic() performs basic sanity checks

 *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY

 *      (if specified)

 *    - drm_mode_validate_flag() checks the modes againt basic connector

 *      capabilites (interlace_allowed,doublescan_allowed,stereo_allowed)

 *    - the optional connector ->mode_valid() helper can perform driver and/or

 *      hardware specific checks

 *

 * 5. Any mode whose status is not OK is pruned from the connector's modes list,

 *    accompanied by a debug message indicating the reason for the mode's

 *    rejection (see drm_mode_prune_invalid()).

 *

 * Returns:

 * The number of modes found on @connector.