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
Signed-off-by: Suraj Kandpal <[email protected]> --- drivers/gpu/drm/i915/display/intel_dp_hdcp.c | 22 ++++++++++++-------- 1 file changed, 13 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 eff2da976d2c..fce9b4e27f67 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c +++ b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c @@ -651,20 +651,24 @@ int intel_dp_hdcp2_capable(struct intel_connector *connector, { struct drm_dp_aux *aux; u8 rx_caps[3]; - int ret; + int ret, i; aux = intel_dp_hdcp_get_aux(connector, remote_req); *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; + 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; + 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; } -- 2.25.1
