Add debugfs interface to expose extended wakeup timeout information for
DP connectors. This shows whether a retimer is present, the
current mode (transparent vs non-transparent), and the wakeup timeout
value in milliseconds.
This helps verify whether the extended wakeup timeout is functioning
as expected.

Signed-off-by: Mohammed Bilal <[email protected]>
---
 .../drm/i915/display/intel_display_debugfs.c  | 78 +++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c 
b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index 2614c4863c87..292ee71643da 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -1310,6 +1310,78 @@ static const struct file_operations i915_joiner_fops = {
        .write = i915_joiner_write
 };
 
+static int i915_extended_wakeup_timeout_show(struct seq_file *m, void *data)
+{
+       struct intel_connector *connector = m->private;
+       struct intel_display *display = to_intel_display(connector);
+       struct intel_encoder *encoder = intel_attached_encoder(connector);
+       struct intel_dp *intel_dp;
+       bool retimer_present = false;
+       bool transparent_mode = true;
+       int wakeup_timeout_ms = 1;
+       int lttpr_count;
+       u8 val;
+       int ret;
+
+       if (!encoder)
+               return -ENODEV;
+
+       ret = 
drm_modeset_lock_single_interruptible(&display->drm->mode_config.connection_mutex);
+       if (ret)
+               return ret;
+       if (connector->base.status != connector_status_connected) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+       intel_dp = enc_to_intel_dp(encoder);
+       lttpr_count = drm_dp_lttpr_count(intel_dp->lttpr_common_caps);
+       retimer_present = (lttpr_count > 0);
+       transparent_mode = intel_dp_lttpr_transparent_mode_enabled(intel_dp);
+
+       if (transparent_mode) {
+               ret = drm_dp_dpcd_read_data(&intel_dp->aux,
+                                           
DP_EXTENDED_DPRX_SLEEP_WAKE_TIMEOUT_REQUEST,
+                                           &val, 1);
+               if (!ret) {
+                       static const u8 timeout_mapping[] = {
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_1_MS] = 1,
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_20_MS] = 20,
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_40_MS] = 40,
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_60_MS] = 60,
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_80_MS] = 80,
+                               [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_100_MS] = 
100,
+                       };
+
+                       if (val < ARRAY_SIZE(timeout_mapping) && 
timeout_mapping[val])
+                               wakeup_timeout_ms = timeout_mapping[val];
+               }
+       } else {
+               ret = drm_dp_dpcd_read_data(&intel_dp->aux,
+                                           
DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT,
+                                           &val, 1);
+
+               if (!ret) {
+
+                       int timeout_val = val & 
DP_EXTENDED_WAKE_TIMEOUT_REQUEST_MASK;
+
+                       wakeup_timeout_ms = timeout_val ? (timeout_val * 10) : 
1;
+               }
+       }
+
+       if (ret)
+               wakeup_timeout_ms = -1;
+
+       seq_printf(m, "retimer_present: %s\n", retimer_present ? "yes" : "no");
+       seq_printf(m, "mode: %s\n", transparent_mode ? "transparent" : 
"non-transparent");
+       seq_printf(m, "wakeup_timeout_ms: %d\n", wakeup_timeout_ms);
+
+out:
+       drm_modeset_unlock(&display->drm->mode_config.connection_mutex);
+       return ret;
+}
+DEFINE_SHOW_ATTRIBUTE(i915_extended_wakeup_timeout);
+
 /**
  * intel_connector_debugfs_add - add i915 specific connector debugfs files
  * @connector: pointer to a registered intel_connector
@@ -1335,6 +1407,12 @@ void intel_connector_debugfs_add(struct intel_connector 
*connector)
        intel_dp_link_training_debugfs_add(connector);
        intel_link_bw_connector_debugfs_add(connector);
 
+       if (DISPLAY_VER(display) >= 30 &&
+           connector_type == DRM_MODE_CONNECTOR_DisplayPort && 
!connector->mst.dp) {
+               debugfs_create_file("i915_extended_wakeup_timeout", 0444, root,
+                                   connector, 
&i915_extended_wakeup_timeout_fops);
+       }
+
        if (DISPLAY_VER(display) >= 11 &&
            ((connector_type == DRM_MODE_CONNECTOR_DisplayPort && 
!connector->mst.dp) ||
             connector_type == DRM_MODE_CONNECTOR_eDP)) {
-- 
2.48.1

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