drm/i915/dp: Initialize the source OUI write timestamp always

If the source OUI DPCD register value matches the expected Intel OUI
value, the write timestamp doesn't get updated leaving it at the 0
initial value if the OUI wasn't written before. This can lead to an
incorrect wait duration in intel_dp_wait_source_oui(), since jiffies is
not inited to 0 in general (on a 32 bit system INITIAL_JIFFIES is set to
5 minutes ahead of wrap-around). Fix this by intializing the write
timestamp in the above case as well.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241025160259.3088727-4-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index b86ede9a1aa5734f30c48300921cba8bd01dc123..735890334de3eecfa0f8575e38496a6cad251704 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3418,8 +3418,11 @@ intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful)
                if (drm_dp_dpcd_read(&intel_dp->aux, DP_SOURCE_OUI, buf, sizeof(buf)) < 0)
                        drm_err(&i915->drm, "Failed to read source OUI\n");
 
-               if (memcmp(oui, buf, sizeof(oui)) == 0)
+               if (memcmp(oui, buf, sizeof(oui)) == 0) {
+                       /* Assume the OUI was written now. */
+                       intel_dp->last_oui_write = jiffies;
                        return;
+               }
        }
 
        if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) < 0)