drm/xe: Enable W=1 warnings by default

Like done in commit 2250c7e ("drm/i915: enable W=1 warnings by default")
for i915, enable W=1 warnings by default in xe.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/Makefile

@@ -3,25 +3,34 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-# Add a set of useful warning flags and enable -Werror for CI to prevent
-# trivial mistakes from creeping in. We have to do this piecemeal as we reject
-# any patch that isn't warning clean, so turning on -Wall -Wextra (or W=1) we
-# need to filter out dubious warnings.  Still it is our interest
-# to keep running locally with W=1 C=1 until we are completely clean.
-#
-# Note the danger in using -Wall -Wextra is that when CI updates gcc we
-# will most likely get a sudden build breakage... Hopefully we will fix
-# new warnings before CI updates!
-subdir-ccflags-y := -Wall -Wextra
-subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)
-subdir-ccflags-y += $(call cc-disable-warning, type-limits)
-subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
-subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
-# clang warnings
-subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
-subdir-ccflags-y += $(call cc-disable-warning, sometimes-uninitialized)
-subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
-subdir-ccflags-y += $(call cc-disable-warning, frame-address)
+# Unconditionally enable W=1 warnings locally
+# --- begin copy-paste W=1 warnings from scripts/Makefile.extrawarn
+subdir-ccflags-y += -Wextra -Wunused -Wno-unused-parameter
+subdir-ccflags-y += -Wmissing-declarations
+subdir-ccflags-y += $(call cc-option, -Wrestrict)
+subdir-ccflags-y += -Wmissing-format-attribute
+subdir-ccflags-y += -Wmissing-prototypes
+subdir-ccflags-y += -Wold-style-definition
+subdir-ccflags-y += -Wmissing-include-dirs
+subdir-ccflags-y += $(call cc-option, -Wunused-but-set-variable)
+subdir-ccflags-y += $(call cc-option, -Wunused-const-variable)
+subdir-ccflags-y += $(call cc-option, -Wpacked-not-aligned)
+subdir-ccflags-y += $(call cc-option, -Wformat-overflow)
+subdir-ccflags-y += $(call cc-option, -Wformat-truncation)
+subdir-ccflags-y += $(call cc-option, -Wstringop-overflow)
+subdir-ccflags-y += $(call cc-option, -Wstringop-truncation)
+# The following turn off the warnings enabled by -Wextra
+ifeq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
+subdir-ccflags-y += -Wno-missing-field-initializers
+subdir-ccflags-y += -Wno-type-limits
+subdir-ccflags-y += -Wno-shift-negative-value
+endif
+ifeq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
+subdir-ccflags-y += -Wno-sign-compare
+endif
+# --- end copy-paste
+
+# Enable -Werror in CI and development
 subdir-ccflags-$(CONFIG_DRM_XE_WERROR) += -Werror
 
 subdir-ccflags-y += -I$(obj) -I$(srctree)/$(src)