During automated test request for link training we are supposed to
read the TEST_LANE_COUNT and TEST_LINK_RATE dpcd registers and use
respective values in the next link training. This patch adds
reading and updating of these values.
Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx>
Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 2a14603..0402a4b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4045,9 +4045,34 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
return true;
}
+/*
+ * This function reads TEST_LANE_COUNT & TEST_LINK_RATE and updates
+ * them to cached dpcd values, thus the new values are implicitly
+ * used by rest of the code without need to be aware of the change.
+ */
static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
{
uint8_t test_result = DP_TEST_ACK;
+ uint8_t dpcd_val, ret;
+
+ ret = intel_dp_dpcd_read_wake(&intel_dp->aux,
+ DP_TEST_LANE_COUNT,
+ &dpcd_val, 1);
+
+ /* update values only if read returned 1 byte */
+ if (ret == 1) {
+ dpcd_val &= DP_MAX_LANE_COUNT_MASK;
+ intel_dp->dpcd[DP_MAX_LANE_COUNT] &= ~(DP_MAX_LANE_COUNT_MASK);
+ intel_dp->dpcd[DP_MAX_LANE_COUNT] |= dpcd_val;
+ }
+
+ ret = intel_dp_dpcd_read_wake(&intel_dp->aux,
+ DP_TEST_LINK_RATE,
+ &dpcd_val, 1);
+
+ if (ret == 1)
+ intel_dp->dpcd[DP_MAX_LINK_RATE] = dpcd_val;
+
return test_result;
}
--
2.6.1
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