drm/i915: Spam less on dp aux send/receive problems

If we encounter frequent problems with dp aux channel
communications, we end up spamming the dmesg with the
exact similar trace and status.

Inject a new backtrace only if we have new information
to share as otherwise we flush out all other important
stuff.

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4b5c6a8..7eabd11 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -849,8 +849,15 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
        }
 
        if (try == 3) {
-               WARN(1, "dp_aux_ch not started status 0x%08x\n",
-                    I915_READ(ch_ctl));
+               static u32 last_status = -1;
+               const u32 status = I915_READ(ch_ctl);
+
+               if (status != last_status) {
+                       WARN(1, "dp_aux_ch not started status 0x%08x\n",
+                            status);
+                       last_status = status;
+               }
+
                ret = -EBUSY;
                goto out;
        }