vga_switcheroo: Constify vga_switcheroo_handler

vga_switcheroo_client_ops has always been declared const since its
introduction with 26ec685f ("vga_switcheroo: Introduce struct
vga_switcheroo_client_ops").

Do so for vga_switcheroo_handler as well.

 drivers/gpu/drm/amd/amdgpu/amdgpu.ko:
   6 .rodata       00009888
- 19 .data         00001f00
+ 19 .data         00001ee0
 drivers/gpu/drm/nouveau/nouveau.ko:
   6 .rodata       000460b8
  17 .data         00018fe0
 drivers/gpu/drm/radeon/radeon.ko:
-  7 .rodata       00030944
+  7 .rodata       00030964
- 21 .data         0000d6a0
+ 21 .data         0000d678
 drivers/platform/x86/apple-gmux.ko:
-  7 .rodata       00000140
+  7 .rodata       00000160
- 11 .data         000000e0
+ 11 .data         000000b8

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Reviewed-by: Christian König <christian.koenig@amd.com>.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c

@@ -501,7 +501,7 @@ static int amdgpu_atpx_get_client_id(struct pci_dev *pdev)
 		return VGA_SWITCHEROO_DIS;
 }
 
-static struct vga_switcheroo_handler amdgpu_atpx_handler = {
+static const struct vga_switcheroo_handler amdgpu_atpx_handler = {
 	.switchto = amdgpu_atpx_switchto,
 	.power_state = amdgpu_atpx_power_state,
 	.init = amdgpu_atpx_init,

drivers/gpu/drm/nouveau/nouveau_acpi.c

@@ -206,7 +206,7 @@ static int nouveau_dsm_get_client_id(struct pci_dev *pdev)
 	return VGA_SWITCHEROO_DIS;
 }
 
-static struct vga_switcheroo_handler nouveau_dsm_handler = {
+static const struct vga_switcheroo_handler nouveau_dsm_handler = {
 	.switchto = nouveau_dsm_switchto,
 	.power_state = nouveau_dsm_power_state,
 	.get_client_id = nouveau_dsm_get_client_id,

drivers/gpu/drm/radeon/radeon_atpx_handler.c

@@ -499,7 +499,7 @@ static int radeon_atpx_get_client_id(struct pci_dev *pdev)
 		return VGA_SWITCHEROO_DIS;
 }
 
-static struct vga_switcheroo_handler radeon_atpx_handler = {
+static const struct vga_switcheroo_handler radeon_atpx_handler = {
 	.switchto = radeon_atpx_switchto,
 	.power_state = radeon_atpx_power_state,
 	.init = radeon_atpx_init,

drivers/gpu/vga/vga_switcheroo.c

@@ -140,7 +140,7 @@ struct vgasr_priv {
 	int registered_clients;
 	struct list_head clients;
 
-	struct vga_switcheroo_handler *handler;
+	const struct vga_switcheroo_handler *handler;
 };
 
 #define ID_BIT_AUDIO		0x100
@@ -195,7 +195,7 @@ static void vga_switcheroo_enable(void)
  *
  * Return: 0 on success, -EINVAL if a handler was already registered.
  */
-int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
+int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler)
 {
 	mutex_lock(&vgasr_mutex);
 	if (vgasr_priv.handler) {

drivers/platform/x86/apple-gmux.c

@@ -346,7 +346,7 @@ gmux_active_client(struct apple_gmux_data *gmux_data)
 	return VGA_SWITCHEROO_DIS;
 }
 
-static struct vga_switcheroo_handler gmux_handler = {
+static const struct vga_switcheroo_handler gmux_handler = {
 	.switchto = gmux_switchto,
 	.power_state = gmux_set_power_state,
 	.get_client_id = gmux_get_client_id,

include/linux/vga_switcheroo.h

@@ -137,7 +137,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 void vga_switcheroo_client_fb_set(struct pci_dev *dev,
 				  struct fb_info *info);
 
-int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler);
+int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler);
 void vga_switcheroo_unregister_handler(void);
 
 int vga_switcheroo_process_delayed_switch(void);
@@ -155,7 +155,7 @@ static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
 static inline int vga_switcheroo_register_client(struct pci_dev *dev,
 		const struct vga_switcheroo_client_ops *ops, bool driver_power_control) { return 0; }
 static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
-static inline int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { return 0; }
+static inline int vga_switcheroo_register_handler(const struct vga_switcheroo_handler *handler) { return 0; }
 static inline int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 	const struct vga_switcheroo_client_ops *ops,
 	enum vga_switcheroo_client_id id) { return 0; }