diff options
| author | Suraj Kandpal <suraj.kandpal@intel.com> | 2024-02-26 12:00:52 +0530 |
|---|---|---|
| committer | Ankit Nautiyal <ankit.k.nautiyal@intel.com> | 2024-02-27 13:20:20 +0530 |
| commit | 610d7bc2e23c83024cd2c943bf91acb83b7e17fd (patch) | |
| tree | 1e4e5f2de2924a05220e7d53af4cb4c0e8369ab6 /drivers/gpu/drm/i915 | |
| parent | 66bd692404a6284ee2cf85968a4018cf212398be (diff) | |
drm/i915/hdcp: Read Rxcaps for robustibility
We see some monitors and docks report incorrect hdcp version
and capability in first few reads so we read rx_caps three times
before we conclude the monitor's or docks HDCP capability
--v2
-Add comment to justify the 3 time read loop for hdcp capability[Ankit]
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226063051.1685326-7-suraj.kandpal@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_hdcp.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c index 99220f970039..b98a87883fef 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c +++ b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c @@ -644,18 +644,29 @@ int _intel_dp_hdcp2_get_capability(struct drm_dp_aux *aux, bool *capable) { u8 rx_caps[3]; - int ret; + int ret, i; *capable = false; - ret = drm_dp_dpcd_read(aux, - DP_HDCP_2_2_REG_RX_CAPS_OFFSET, - rx_caps, HDCP_2_2_RXCAPS_LEN); - if (ret != HDCP_2_2_RXCAPS_LEN) - return ret >= 0 ? -EIO : ret; - if (rx_caps[0] == HDCP_2_2_RX_CAPS_VERSION_VAL && - HDCP_2_2_DP_HDCP_CAPABLE(rx_caps[2])) - *capable = true; + /* + * Some HDCP monitors act really shady by not giving the correct hdcp + * capability on the first rx_caps read and usually take an extra read + * to give the capability. We read rx_caps three times before we + * declare a monitor not capable of HDCP 2.2. + */ + for (i = 0; i < 3; i++) { + ret = drm_dp_dpcd_read(aux, + DP_HDCP_2_2_REG_RX_CAPS_OFFSET, + rx_caps, HDCP_2_2_RXCAPS_LEN); + if (ret != HDCP_2_2_RXCAPS_LEN) + return ret >= 0 ? -EIO : ret; + + if (rx_caps[0] == HDCP_2_2_RX_CAPS_VERSION_VAL && + HDCP_2_2_DP_HDCP_CAPABLE(rx_caps[2])) { + *capable = true; + break; + } + } return 0; } |