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@xxxxxxxxxx>
---
drivers/gpu/drm/drm_ioctl.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index ea10e9a26a..08e48bda23 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -469,6 +469,29 @@ static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value)
return 0;
}
+static int drm_mode_addfb2_check(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.
+ */
+ return -EINVAL;
+ }
+#endif
+ return drm_mode_addfb2(dev, data, file_priv);
+}
+
/*
* Get version information
*
@@ -645,7 +668,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb_ioctl, DRM_UNLOCKED),
- DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2, DRM_UNLOCKED),
+ DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2_check, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb_ioctl, DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER|DRM_UNLOCKED),
DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER|DRM_UNLOCKED),
--
2.9.3
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