--- /dev/null
+From foo@baz Thu Aug 31 08:30:43 CEST 2017
+Date: Thu, 31 Aug 2017 08:30:43 +0200
+To: Greg KH <gregkh@linuxfoundation.org>
+From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Subject: drm/i915: fix compiler warning in drivers/gpu/drm/i915/intel_uncore.c
+
+From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+When building with gcc-7, the following warning happens:
+
+drivers/gpu/drm/i915/intel_uncore.c: In function ‘hsw_unclaimed_reg_detect’:
+drivers/gpu/drm/i915/intel_uncore.c:638:36: warning: decrement of a boolean expression [-Wbool-operation]
+ i915.mmio_debug = mmio_debug_once--;
+ ^~
+
+As it's really not wise to -- on a boolean value.
+
+Commit 7571494004d8 ("drm/i915: Do one shot unclaimed mmio detection
+less frequently") which showed up in 4.6-rc1 does solve this issue, by
+rewriting the mmio detection logic, but that isn't really good to
+backport to 4.4-stable, so just fix up the obvious logic here to do the
+right thing.
+
+Cc: Chris Wilson <chris@chris-wilson.co.uk>
+Cc: Paulo Zanoni <przanoni@gmail.com>
+Cc: Mika Kuoppala <mika.kuoppala@intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/gpu/drm/i915/intel_uncore.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/gpu/drm/i915/intel_uncore.c
++++ b/drivers/gpu/drm/i915/intel_uncore.c
+@@ -635,7 +635,8 @@ hsw_unclaimed_reg_detect(struct drm_i915
+ "enabling oneshot unclaimed register reporting. "
+ "Please use i915.mmio_debug=N for more information.\n");
+ __raw_i915_write32(dev_priv, FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
+- i915.mmio_debug = mmio_debug_once--;
++ i915.mmio_debug = mmio_debug_once;
++ mmio_debug_once = false;
+ }
+ }
+