drm: fix drm_mode_addfb() on big endian machines.
Userspace on big endian machhines typically expects the ADDFB ioctl
returns a big endian framebuffer. drm_mode_addfb() will call
drm_mode_addfb2() unconditionally with little endian DRM_FORMAT_*
values though, which is wrong. This patch fixes that.
Drivers (both kernel and xorg) have quirks in place to deal with the
broken drm_mode_addfb() behavior. Because of this we can't just change
drm_mode_addfb() behavior for everybody without breaking things. Add
the quirk_addfb_prefer_host_byte_order field to mode_config, so drivers
can opt-in.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180905060445.15008-5-kraxel@redhat.com
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 5d29f4b..928e417 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -812,6 +812,20 @@ struct drm_mode_config {
bool quirk_addfb_prefer_xbgr_30bpp;
/**
+ * @quirk_addfb_prefer_host_byte_order:
+ *
+ * When set to true drm_mode_addfb() will pick host byte order
+ * pixel_format when calling drm_mode_addfb2(). This is how
+ * drm_mode_addfb() should have worked from day one. It
+ * didn't though, so we ended up with quirks in both kernel
+ * and userspace drivers to deal with the broken behavior.
+ * Simply fixing drm_mode_addfb() unconditionally would break
+ * these drivers, so add a quirk bit here to allow drivers
+ * opt-in.
+ */
+ bool quirk_addfb_prefer_host_byte_order;
+
+ /**
* @async_page_flip: Does this device support async flips on the primary
* plane?
*/