Implements some of the basic EDID tests for Displayport compliance. These tests
include reading the EDID, verifying the checksum and writing the test responses
back to the sink device.
Signed-off-by: Todd Previte <tprevite@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 36 +++++++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 43fcabe..d060853 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3352,8 +3352,42 @@ intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
static uint8_t
intel_dp_autotest_edid(struct intel_dp *intel_dp)
{
+ struct drm_connector *connector = &intel_dp->attached_connector->base;
+ struct i2c_adapter *adapter = &intel_dp->aux.ddc;
+ struct edid *edid_read = NULL;
+ uint8_t *edid_data = NULL;
uint8_t test_result = DP_TEST_NAK;
- return test_result;
+ uint32_t i = 0, ret = 0, checksum = 0;
+ struct drm_display_mode *use_mode = NULL;
+ dp_compliance_mode comp_mode_type = DP_COMPLIANCE_MODE_PREFERRED;
+ int mode_count = 0;
+
+ edid_read = drm_get_edid(connector, adapter);
+
+ DRM_DEBUG_KMS("Displayport: EDID automated test\n");
+
+ if (edid_read) {
+ test_result = true;
+ edid_data = (uint8_t*) edid_read;
+ // Compute checksum
+ for (i = 0; i < 128; i++)
+ checksum += edid_data[i];
+
+ DRM_DEBUG_KMS("Displayport: EDID test - computed byte sum = %02x\n", checksum);
+ // Verify EDID checksum
+ if (checksum % 256 == 0) {
+ /* Write the checksum to EDID checksum register */
+ ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TEST_EDID_CHECKSUM, &edid_read->checksum, 1);
+ // Reponse is ACK and and checksum written
+ test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;
+ DRM_DEBUG_KMS("Displayport: EDID test - checksum = %02x\n", edid_read->checksum);
+ }
+ else {
+ // Invalid checksum, set for failsafe mode
+ comp_mode_type = DP_COMPLIANCE_MODE_FAILSAFE;
+ }
+ }
+ return test_result;
}
/* Displayport compliance testing - PHY pattern testing */
--
1.9.1
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