drm/i915: Just clear the mmiodebug before a register access

commit f856f847 upstream.

When we enable the per-register access mmiodebug, it is to detect which
access is illegal. Reporting on earlier untraced access outside of the
mmiodebug does not help debugging (as the suspicion is immediately put
upon the current register which is not at fault)!

References: https://bugs.freedesktop.org/show_bug.cgi?id=97985Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161003124516.12388-1-chris@chris-wilson.co.uk
(cherry picked from commit dda96033)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/i915/intel_uncore.c

@@ -796,10 +796,9 @@ __unclaimed_reg_debug(struct drm_i915_private *dev_priv,
 		      const bool read,
 		      const bool before)
 {
-	if (WARN(check_for_unclaimed_mmio(dev_priv),
-		 "Unclaimed register detected %s %s register 0x%x\n",
-		 before ? "before" : "after",
-		 read ? "reading" : "writing to",
+	if (WARN(check_for_unclaimed_mmio(dev_priv) && !before,
+		 "Unclaimed %s register 0x%x\n",
+		 read ? "read from" : "write to",
 		 i915_mmio_reg_offset(reg)))
 		i915.mmio_debug--; /* Only report the first N failures */
 }