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drm/dp: Add drm_dp_downstream_mode()

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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: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904115354.25336-14-ville.syrjala@linux.intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2020-09-04 14:53:49 +03:00
parent b7feffd584
commit 7af655bce2
4 changed files with 98 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
drivers/gpu/drm/drm_dp_helper.c
View File

@ -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

28
drivers/gpu/drm/drm_edid.c
View File

@ -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)
{

12
include/drm/drm_dp_helper.h
View File

@ -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],

4
include/drm/drm_edid.h
View File

@ -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__ */