Commit 7af655bc authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/dp: Add drm_dp_downstream_mode() 



The downstream facing port caps in the DPCD can give us a hint
as to what kind of display mode the sink can use if it doesn't
have an EDID. Use that information to pick a suitable mode.

v2: Use Returns: for kdoc (Lyude)
    Add kdocs for drm_display_mode_from_cea_vic() (Lyude)

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904115354.25336-14-ville.syrjala@linux.intel.com


Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent b7feffd5

drivers/gpu/drm/drm_dp_helper.c

+54 −0
Original line number Diff line number Diff line
@@ -808,6 +808,60 @@ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], 
}

EXPORT_SYMBOL(drm_dp_downstream_max_bpc);



/**

 * drm_dp_downstream_mode() - return a mode for downstream facing port

 * @dpcd: DisplayPort configuration data

 * @port_cap: port capabilities

 *

 * Provides a suitable mode for downstream facing ports without EDID.

 *

 * Returns: A new drm_display_mode on success or NULL on failure

 */

struct drm_display_mode *

drm_dp_downstream_mode(struct drm_device *dev,

		       const u8 dpcd[DP_RECEIVER_CAP_SIZE],

		       const u8 port_cap[4])



{

	u8 vic;



	if (!drm_dp_is_branch(dpcd))

		return NULL;



	if (dpcd[DP_DPCD_REV] < 0x11)

		return NULL;



	switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {

	case DP_DS_PORT_TYPE_NON_EDID:

		switch (port_cap[0] & DP_DS_NON_EDID_MASK) {

		case DP_DS_NON_EDID_720x480i_60:

			vic = 6;

			break;

		case DP_DS_NON_EDID_720x480i_50:

			vic = 21;

			break;

		case DP_DS_NON_EDID_1920x1080i_60:

			vic = 5;

			break;

		case DP_DS_NON_EDID_1920x1080i_50:

			vic = 20;

			break;

		case DP_DS_NON_EDID_1280x720_60:

			vic = 4;

			break;

		case DP_DS_NON_EDID_1280x720_50:

			vic = 19;

			break;

		default:

			return NULL;

		}

		return drm_display_mode_from_cea_vic(dev, vic);

	default:

		return NULL;

	}

}

EXPORT_SYMBOL(drm_dp_downstream_mode);



/**

 * drm_dp_downstream_id() - identify branch device

 * @aux: DisplayPort AUX channel

drivers/gpu/drm/drm_edid.c

+28 −0
Original line number Diff line number Diff line
@@ -3738,6 +3738,34 @@ drm_add_cmdb_modes(struct drm_connector *connector, u8 svd) 
	bitmap_set(hdmi->y420_cmdb_modes, vic, 1);

}



/**

 * drm_display_mode_from_cea_vic() - return a mode for CEA VIC

 * @dev: DRM device

 * @vic: CEA VIC of the mode

 *

 * Creates a new mode matching the specified CEA VIC.

 *

 * Returns: A new drm_display_mode on success or NULL on failure

 */

struct drm_display_mode *

drm_display_mode_from_cea_vic(struct drm_device *dev,

			      u8 video_code)

{

	const struct drm_display_mode *cea_mode;

	struct drm_display_mode *newmode;



	cea_mode = cea_mode_for_vic(video_code);

	if (!cea_mode)

		return NULL;



	newmode = drm_mode_duplicate(dev, cea_mode);

	if (!newmode)

		return NULL;



	return newmode;

}

EXPORT_SYMBOL(drm_display_mode_from_cea_vic);



static int

do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len)

{

include/drm/drm_dp_helper.h

+12 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 
#include <linux/types.h>

#include <drm/drm_connector.h>



struct drm_device;



/*

 * Unless otherwise noted, all values are from the DP 1.1a spec.  Note that

 * DP and DPCD versions are independent.  Differences from 1.0 are not noted,
@@ -385,6 +387,13 @@ 
# define DP_DS_PORT_TYPE_DP_DUALMODE        5

# define DP_DS_PORT_TYPE_WIRELESS           6

# define DP_DS_PORT_HPD			    (1 << 3)

# define DP_DS_NON_EDID_MASK		    (0xf << 4)

# define DP_DS_NON_EDID_720x480i_60	    (1 << 4)

# define DP_DS_NON_EDID_720x480i_50	    (2 << 4)

# define DP_DS_NON_EDID_1920x1080i_60	    (3 << 4)

# define DP_DS_NON_EDID_1920x1080i_50	    (4 << 4)

# define DP_DS_NON_EDID_1280x720_60	    (5 << 4)

# define DP_DS_NON_EDID_1280x720_50	    (7 << 4)

/* offset 1 for VGA is maximum megapixels per second / 8 */

/* offset 1 for DVI/HDMI is maximum TMDS clock in Mbps / 2.5 */

/* offset 2 for VGA/DVI/HDMI */
@@ -1654,6 +1663,9 @@ int drm_dp_downstream_min_tmds_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], 
int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

			      const u8 port_cap[4],

			      const struct edid *edid);

struct drm_display_mode *drm_dp_downstream_mode(struct drm_device *dev,

						const u8 dpcd[DP_RECEIVER_CAP_SIZE],

						const u8 port_cap[4]);

int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);

void drm_dp_downstream_debug(struct seq_file *m,

			     const u8 dpcd[DP_RECEIVER_CAP_SIZE],

include/drm/drm_edid.h

+4 −0
Original line number Diff line number Diff line
@@ -517,4 +517,8 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name, 
struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,

					   int hsize, int vsize, int fresh,

					   bool rb);

struct drm_display_mode *

drm_display_mode_from_cea_vic(struct drm_device *dev,

			      u8 video_code);



#endif /* __DRM_EDID_H__ */