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drm/dp: Pimp drm_dp_downstream_max_bpc()

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Deal with more cases in drm_dp_downstream_max_bpc():
- DPCD 1.0 -> assume 8bpc for non-DP
- DPCD 1.1+ DP (or DP++ with DP sink) -> allow anything
- DPCD 1.1+ TMDS -> check the caps, assume 8bpc if the value is crap
- anything else -> assume 8bpc

v2: Use Returns: for kdoc (Lyude)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200904115354.25336-8-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 14:53:43 +03:00
parent 38784f6f88
commit 42f2562ca1
4 changed files with 47 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
drivers/gpu/drm/drm_dp_helper.c
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@@ -653,36 +653,44 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
EXPORT_SYMBOL(drm_dp_downstream_max_clock);
/**
* drm_dp_downstream_max_bpc() - extract branch device max
* drm_dp_downstream_max_bpc() - extract downstream facing port max
* bits per component
* @dpcd: DisplayPort configuration data
* @port_cap: port capabilities
*
* See also:
* drm_dp_read_downstream_info()
* drm_dp_downstream_max_clock()
* @port_cap: downstream facing port capabilities
* @edid: EDID
*
* Returns: Max bpc on success or 0 if max bpc not defined
*/
int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
const u8 port_cap[4])
const u8 port_cap[4],
const struct edid *edid)
{
int type = port_cap[0] & DP_DS_PORT_TYPE_MASK;
bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
DP_DETAILED_CAP_INFO_AVAILABLE;
int bpc;
if (!detailed_cap_info)
if (!drm_dp_is_branch(dpcd))
return 0;
switch (type) {
case DP_DS_PORT_TYPE_VGA:
case DP_DS_PORT_TYPE_DVI:
case DP_DS_PORT_TYPE_HDMI:
case DP_DS_PORT_TYPE_DP_DUALMODE:
bpc = port_cap[2] & DP_DS_MAX_BPC_MASK;
if (dpcd[DP_DPCD_REV] < 0x11) {
switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) {
case DP_DWN_STRM_PORT_TYPE_DP:
return 0;
default:
return 8;
}
}
switch (bpc) {
switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {
case DP_DS_PORT_TYPE_DP:
return 0;
case DP_DS_PORT_TYPE_DP_DUALMODE:
if (is_edid_digital_input_dp(edid))
return 0;
fallthrough;
case DP_DS_PORT_TYPE_HDMI:
case DP_DS_PORT_TYPE_DVI:
case DP_DS_PORT_TYPE_VGA:
if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0)
return 8;
switch (port_cap[2] & DP_DS_MAX_BPC_MASK) {
case DP_DS_8BPC:
return 8;
case DP_DS_10BPC:
@@ -691,10 +699,12 @@ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
return 12;
case DP_DS_16BPC:
return 16;
default:
return 8;
}
fallthrough;
break;
default:
return 0;
return 8;
}
}
EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
@@ -717,12 +727,15 @@ EXPORT_SYMBOL(drm_dp_downstream_id);
* @m: pointer for debugfs file
* @dpcd: DisplayPort configuration data
* @port_cap: port capabilities
* @edid: EDID
* @aux: DisplayPort AUX channel
*
*/
void drm_dp_downstream_debug(struct seq_file *m,
const u8 dpcd[DP_RECEIVER_CAP_SIZE],
const u8 port_cap[4], struct drm_dp_aux *aux)
const u8 port_cap[4],
const struct edid *edid,
struct drm_dp_aux *aux)
{
bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
DP_DETAILED_CAP_INFO_AVAILABLE;
@@ -789,7 +802,7 @@ void drm_dp_downstream_debug(struct seq_file *m,
seq_printf(m, "\t\tMax TMDS clock: %d kHz\n", clk);
}
bpc = drm_dp_downstream_max_bpc(dpcd, port_cap);
bpc = drm_dp_downstream_max_bpc(dpcd, port_cap, edid);
if (bpc > 0)
seq_printf(m, "\t\tMax bpc: %d\n", bpc);