drm/i915: use localized __diag_ignore_all() instead of per file

Use localized __diag_push(), __diag_ignore_all() with rationale, and
__diag_pop() for specific initializations instead of blanket disabling
of -Woverride-init across several files.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230525210653.1048972-1-jani.nikula@intel.com

drivers/gpu/drm/i915/Makefile

@@ -23,11 +23,6 @@ subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
 subdir-ccflags-y += $(call cc-disable-warning, frame-address)
 subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
 
-# Fine grained warnings disable
-CFLAGS_i915_pci.o = $(call cc-disable-warning, override-init)
-CFLAGS_display/intel_display_device.o = $(call cc-disable-warning, override-init)
-CFLAGS_display/intel_fbdev.o = $(call cc-disable-warning, override-init)
-
 subdir-ccflags-y += -I$(srctree)/$(src)
 
 # Please keep these build lists sorted!

drivers/gpu/drm/i915/display/intel_display_device.c

@@ -14,6 +14,9 @@
 #include "intel_display_reg_defs.h"
 #include "intel_fbc.h"
 
+__diag_push();
+__diag_ignore_all("-Woverride-init", "Allow overriding inherited members");
+
 static const struct intel_display_device_info no_display = {};
 
 #define PIPE_A_OFFSET		0x70000
@@ -650,6 +653,8 @@ static const struct intel_display_device_info xe_lpdp_display = {
 		BIT(TRANSCODER_C) | BIT(TRANSCODER_D),
 };
 
+__diag_pop();
+
 #undef INTEL_VGA_DEVICE
 #undef INTEL_QUANTA_VGA_DEVICE
 #define INTEL_VGA_DEVICE(id, info) { id, info }

drivers/gpu/drm/i915/display/intel_fbdev.c

@@ -130,6 +130,9 @@ static int intel_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	return i915_gem_fb_mmap(obj, vma);
 }
 
+__diag_push();
+__diag_ignore_all("-Woverride-init", "Allow overriding the default ops");
+
 static const struct fb_ops intelfb_ops = {
 	.owner = THIS_MODULE,
 	DRM_FB_HELPER_DEFAULT_OPS,
@@ -144,6 +147,8 @@ static const struct fb_ops intelfb_ops = {
 	.fb_mmap = intel_fbdev_mmap,
 };
 
+__diag_pop();
+
 static int intelfb_alloc(struct drm_fb_helper *helper,
 			 struct drm_fb_helper_surface_size *sizes)
 {

drivers/gpu/drm/i915/i915_pci.c

@@ -38,6 +38,9 @@
 #include "i915_reg.h"
 #include "intel_pci_config.h"
 
+__diag_push();
+__diag_ignore_all("-Woverride-init", "Allow overriding inherited members");
+
 #define PLATFORM(x) .platform = (x)
 #define GEN(x) \
 	.__runtime.graphics.ip.ver = (x), \
@@ -843,6 +846,8 @@ static const struct intel_device_info mtl_info = {
 
 #undef PLATFORM
 
+__diag_pop();
+
 /*
  * Make sure any device matches here are from most specific to most
  * general.  For example, since the Quanta match is based on the subsystem