[Intel-gfx] [PATCH] drm/i915: Force clean compilation with -Werror

[Chris Wilson]

Our driver compiles clean (nowadays thanks to 0day) but for me, at least,
it would be beneficial if the compiler threw an error rather than a
warning when it found a piece of suspect code. (I use this to
compile-check patch series and want to break on the first compiler error
in order to fix the patch.)

v2: Kick off a new "Debugging" submenu for i915.ko

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/Kconfig       | 8 ++++++++
 drivers/gpu/drm/i915/Kconfig.debug | 5 +++++
 drivers/gpu/drm/i915/Makefile      | 2 ++
 3 files changed, 15 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/Kconfig.debug

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 74acca9bcd9d..76c425ca2a2c 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -71,3 +71,11 @@ config DRM_I915_PRELIMINARY_HW_SUPPORT
 	  option changes the default for that module option.
 
 	  If in doubt, say "N".
+
+menu "Debugging"
+
+depends on DRM_I915
+
+source drivers/gpu/drm/i915/Kconfig.debug
+
+endmenu
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
new file mode 100644
index 000000000000..070a03527bc5
--- /dev/null
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -0,0 +1,5 @@
+config DRM_I915_WERROR
+	bool "Force GCC to throw an error instead of a warning when compiling"
+	default n
+	---help---
+	  Add -Werror to the build flags for (and only for) i915.ko
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index b7ddf48e1d75..93d99b744531 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -2,6 +2,8 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
+subdir-ccflags-$(CONFIG_DRM_I915_WERROR) := -Werror
+
 # Please keep these build lists sorted!
 
 # core driver code
-- 
2.1.4