diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 18086423a3a7..886c885c8cf5 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -53,12 +53,31 @@ struct line_buffer {
 	struct pixel_argb_u16 *pixels;
 };
 
+/**
+ * typedef pixel_write_t - These functions are used to read a pixel from a
+ * `struct pixel_argb_u16*`, convert it in a specific format and write it in the @dst_pixels
+ * buffer.
+ *
+ * @dst_pixel: destination address to write the pixel
+ * @in_pixel: pixel to write
+ */
+typedef void (*pixel_write_t)(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel);
+
 struct vkms_writeback_job {
 	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
 	struct vkms_frame_info wb_frame_info;
-	void (*pixel_write)(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel);
+	pixel_write_t pixel_write;
 };
 
+/**
+ * typedef pixel_read_t - These functions are used to read a pixel in the source frame,
+ * convert it to `struct pixel_argb_u16` and write it to @out_pixel.
+ *
+ * @src_pixels: Pointer to the pixel to read
+ * @out_pixel: Pointer to write the converted pixel
+ */
+typedef void (*pixel_read_t)(u8 *src_pixels, struct pixel_argb_u16 *out_pixel);
+
 /**
  * vkms_plane_state - Driver specific plane state
  * @base: base plane state
@@ -69,7 +88,7 @@ struct vkms_writeback_job {
 struct vkms_plane_state {
 	struct drm_shadow_plane_state base;
 	struct vkms_frame_info *frame_info;
-	void (*pixel_read)(u8 *src_buffer, struct pixel_argb_u16 *out_pixel);
+	pixel_read_t pixel_read;
 };
 
 struct vkms_plane {
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index cb7a49b7c8e7..1f5aeba57ad6 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -262,7 +262,7 @@ void vkms_writeback_row(struct vkms_writeback_job *wb,
  *
  * @format: 4cc of the format
  */
-void *get_pixel_conversion_function(u32 format)
+pixel_read_t get_pixel_read_function(u32 format)
 {
 	switch (format) {
 	case DRM_FORMAT_ARGB8888:
@@ -276,7 +276,7 @@ void *get_pixel_conversion_function(u32 format)
 	case DRM_FORMAT_RGB565:
 		return &RGB565_to_argb_u16;
 	default:
-		return NULL;
+		return (pixel_read_t)NULL;
 	}
 }
 
@@ -287,7 +287,7 @@ void *get_pixel_conversion_function(u32 format)
  *
  * @format: 4cc of the format
  */
-void *get_pixel_write_function(u32 format)
+pixel_write_t get_pixel_write_function(u32 format)
 {
 	switch (format) {
 	case DRM_FORMAT_ARGB8888:
@@ -301,6 +301,6 @@ void *get_pixel_write_function(u32 format)
 	case DRM_FORMAT_RGB565:
 		return &argb_u16_to_RGB565;
 	default:
-		return NULL;
+		return (pixel_write_t)NULL;
 	}
 }
diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
index cf59c2ed8e9a..3ecea4563254 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.h
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -5,8 +5,8 @@
 
 #include "vkms_drv.h"
 
-void *get_pixel_conversion_function(u32 format);
+pixel_read_t get_pixel_read_function(u32 format);
 
-void *get_pixel_write_function(u32 format);
+pixel_write_t get_pixel_write_function(u32 format);
 
 #endif /* _VKMS_FORMATS_H_ */
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index d5203f531d96..f68b1b03d632 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -106,6 +106,13 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
 		return;
 
 	fmt = fb->format->format;
+	pixel_read_t pixel_read = get_pixel_read_function(fmt);
+
+	if (!pixel_read) {
+		DRM_WARN("Pixel format is not supported by VKMS planes. State is inchanged\n");
+		return;
+	}
+
 	vkms_plane_state = to_vkms_plane_state(new_state);
 	shadow_plane_state = &vkms_plane_state->base;
 
@@ -124,7 +131,7 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
 	drm_rect_rotate(&frame_info->rotated, drm_rect_width(&frame_info->rotated),
 			drm_rect_height(&frame_info->rotated), frame_info->rotation);
 
-	vkms_plane_state->pixel_read = get_pixel_conversion_function(fmt);
+	vkms_plane_state->pixel_read = pixel_read;
 }
 
 static int vkms_plane_atomic_check(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index c8582df1f739..c92b9f06c4a4 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -140,6 +140,13 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
 	if (!conn_state)
 		return;
 
+	pixel_write_t pixel_write = get_pixel_write_function(wb_format);
+
+	if (!pixel_write) {
+		DRM_WARN("Pixel format is not supported by VKMS writeback. State is inchanged\n");
+		return;
+	}
+
 	vkms_set_composer(&vkmsdev->output, true);
 
 	active_wb = conn_state->writeback_job->priv;
@@ -150,7 +157,7 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
 	crtc_state->wb_pending = true;
 	spin_unlock_irq(&output->composer_lock);
 	drm_writeback_queue_job(wb_conn, connector_state);
-	active_wb->pixel_write = get_pixel_write_function(wb_format);
+	active_wb->pixel_write = pixel_write;
 	drm_rect_init(&wb_frame_info->src, 0, 0, crtc_width, crtc_height);
 	drm_rect_init(&wb_frame_info->dst, 0, 0, crtc_width, crtc_height);
 }
