drm/vkms: add crc sources list

Other drivers are able to list crc sources when accessing
/sys/kernel/debug/dri/.../crtc-0/crc/control

Even though VKMS now supports only 'auto' mode, it is more consistent to
have the list available to the userspace.
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613121802.2193-3-oleg.vasilev@intel.com

drivers/gpu/drm/vkms/vkms_crc.c

@@ -212,6 +212,15 @@ void vkms_crc_work_handle(struct work_struct *work)
 	spin_unlock_irqrestore(&out->state_lock, flags);
 }
 
+static const char * const pipe_crc_sources[] = {"auto"};
+
+const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
+					size_t *count)
+{
+	*count = ARRAY_SIZE(pipe_crc_sources);
+	return pipe_crc_sources;
+}
+
 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
 {
 	int ret = 0;

drivers/gpu/drm/vkms/vkms_crtc.c

@@ -147,6 +147,7 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = {
 	.atomic_destroy_state   = vkms_atomic_crtc_destroy_state,
 	.enable_vblank		= vkms_enable_vblank,
 	.disable_vblank		= vkms_disable_vblank,
+	.get_crc_sources	= vkms_get_crc_sources,
 	.set_crc_source		= vkms_set_crc_source,
 	.verify_crc_source	= vkms_verify_crc_source,
 };

drivers/gpu/drm/vkms/vkms_drv.h

@@ -128,6 +128,8 @@ int vkms_gem_vmap(struct drm_gem_object *obj);
 void vkms_gem_vunmap(struct drm_gem_object *obj);
 
 /* CRC Support */
+const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
+					size_t *count);
 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
 			   size_t *values_cnt);