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

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=97985
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: stable@vger.kernel.org
Link: http://patchwork.freedesktop.org/patch/msgid/20161003124516.12388-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index a9b6c93..ee2306a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/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 */
 }