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path: root/drivers/gpu/drm/i915/display/intel_dp_link_training.c
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Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_dp_link_training.c')
-rw-r--r--drivers/gpu/drm/i915/display/intel_dp_link_training.c76
1 files changed, 59 insertions, 17 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 892d7db7d94f..2ed309534e97 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -34,6 +34,11 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
link_status[3], link_status[4], link_status[5]);
}
+static void intel_dp_reset_lttpr_common_caps(struct intel_dp *intel_dp)
+{
+ memset(&intel_dp->lttpr_common_caps, 0, sizeof(intel_dp->lttpr_common_caps));
+}
+
static void intel_dp_reset_lttpr_count(struct intel_dp *intel_dp)
{
intel_dp->lttpr_common_caps[DP_PHY_REPEATER_CNT -
@@ -81,19 +86,36 @@ static void intel_dp_read_lttpr_phy_caps(struct intel_dp *intel_dp,
static bool intel_dp_read_lttpr_common_caps(struct intel_dp *intel_dp)
{
- if (drm_dp_read_lttpr_common_caps(&intel_dp->aux,
- intel_dp->lttpr_common_caps) < 0) {
- memset(intel_dp->lttpr_common_caps, 0,
- sizeof(intel_dp->lttpr_common_caps));
+ struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+
+ if (intel_dp_is_edp(intel_dp))
return false;
- }
+
+ /*
+ * Detecting LTTPRs must be avoided on platforms with an AUX timeout
+ * period < 3.2ms. (see DP Standard v2.0, 2.11.2, 3.6.6.1).
+ */
+ if (INTEL_GEN(i915) < 10)
+ return false;
+
+ if (drm_dp_read_lttpr_common_caps(&intel_dp->aux,
+ intel_dp->lttpr_common_caps) < 0)
+ goto reset_caps;
drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
"LTTPR common capabilities: %*ph\n",
(int)sizeof(intel_dp->lttpr_common_caps),
intel_dp->lttpr_common_caps);
+ /* The minimum value of LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV is 1.4 */
+ if (intel_dp->lttpr_common_caps[0] < 0x14)
+ goto reset_caps;
+
return true;
+
+reset_caps:
+ intel_dp_reset_lttpr_common_caps(intel_dp);
+ return false;
}
static bool
@@ -106,33 +128,49 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
}
/**
- * intel_dp_lttpr_init - detect LTTPRs and init the LTTPR link training mode
+ * intel_dp_init_lttpr_and_dprx_caps - detect LTTPR and DPRX caps, init the LTTPR link training mode
* @intel_dp: Intel DP struct
*
- * Read the LTTPR common capabilities, switch to non-transparent link training
- * mode if any is detected and read the PHY capabilities for all detected
- * LTTPRs. In case of an LTTPR detection error or if the number of
+ * Read the LTTPR common and DPRX capabilities and switch to non-transparent
+ * link training mode if any is detected and read the PHY capabilities for all
+ * detected LTTPRs. In case of an LTTPR detection error or if the number of
* LTTPRs is more than is supported (8), fall back to the no-LTTPR,
* transparent mode link training mode.
*
* Returns:
- * >0 if LTTPRs were detected and the non-transparent LT mode was set
+ * >0 if LTTPRs were detected and the non-transparent LT mode was set. The
+ * DPRX capabilities are read out.
* 0 if no LTTPRs or more than 8 LTTPRs were detected or in case of a
- * detection failure and the transparent LT mode was set
+ * detection failure and the transparent LT mode was set. The DPRX
+ * capabilities are read out.
+ * <0 Reading out the DPRX capabilities failed.
*/
-int intel_dp_lttpr_init(struct intel_dp *intel_dp)
+int intel_dp_init_lttpr_and_dprx_caps(struct intel_dp *intel_dp)
{
int lttpr_count;
bool ret;
int i;
- if (intel_dp_is_edp(intel_dp))
- return 0;
-
ret = intel_dp_read_lttpr_common_caps(intel_dp);
+
+ /* The DPTX shall read the DPRX caps after LTTPR detection. */
+ if (drm_dp_read_dpcd_caps(&intel_dp->aux, intel_dp->dpcd)) {
+ intel_dp_reset_lttpr_common_caps(intel_dp);
+ return -EIO;
+ }
+
if (!ret)
return 0;
+ /*
+ * The 0xF0000-0xF02FF range is only valid if the DPCD revision is
+ * at least 1.4.
+ */
+ if (intel_dp->dpcd[DP_DPCD_REV] < 0x14) {
+ intel_dp_reset_lttpr_common_caps(intel_dp);
+ return 0;
+ }
+
lttpr_count = drm_dp_lttpr_count(intel_dp->lttpr_common_caps);
/*
* Prevent setting LTTPR transparent mode explicitly if no LTTPRs are
@@ -172,7 +210,7 @@ int intel_dp_lttpr_init(struct intel_dp *intel_dp)
return lttpr_count;
}
-EXPORT_SYMBOL(intel_dp_lttpr_init);
+EXPORT_SYMBOL(intel_dp_init_lttpr_and_dprx_caps);
static u8 dp_voltage_max(u8 preemph)
{
@@ -807,7 +845,11 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
* TODO: Reiniting LTTPRs here won't be needed once proper connector
* HW state readout is added.
*/
- int lttpr_count = intel_dp_lttpr_init(intel_dp);
+ int lttpr_count = intel_dp_init_lttpr_and_dprx_caps(intel_dp);
+
+ if (lttpr_count < 0)
+ /* Still continue with enabling the port and link training. */
+ lttpr_count = 0;
if (!intel_dp_link_train_all_phys(intel_dp, crtc_state, lttpr_count))
intel_dp_schedule_fallback_link_training(intel_dp, crtc_state);