drm: refuse ADDFB2 ioctl for broken bigendian drivers
Drivers must set the quirk_addfb_prefer_host_byte_order quirk to make
the drm_mode_addfb() compat code work correctly on bigendian machines.
If they don't they interpret pixel_format values incorrectly for bug
compatibility, which in turn implies the ADDFB2 ioctl does not work
correctly then. So block it to make userspace fallback to ADDFB.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180907073213.20410-1-kraxel@redhat.com
diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 227f52e..6eaacd4 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -369,6 +369,30 @@ int drm_mode_addfb2(struct drm_device *dev,
return 0;
}
+int drm_mode_addfb2_ioctl(struct drm_device *dev,
+ void *data, struct drm_file *file_priv)
+{
+#ifdef __BIG_ENDIAN
+ if (!dev->mode_config.quirk_addfb_prefer_host_byte_order) {
+ /*
+ * Drivers must set the
+ * quirk_addfb_prefer_host_byte_order quirk to make
+ * the drm_mode_addfb() compat code work correctly on
+ * bigendian machines.
+ *
+ * If they don't they interpret pixel_format values
+ * incorrectly for bug compatibility, which in turn
+ * implies the ADDFB2 ioctl does not work correctly
+ * then. So block it to make userspace fallback to
+ * ADDFB.
+ */
+ DRM_DEBUG_KMS("addfb2 broken on bigendian");
+ return -EINVAL;
+ }
+#endif
+ return drm_mode_addfb2(dev, data, file_priv);
+}
+
struct drm_mode_rmfb_work {
struct work_struct work;
struct list_head fbs;