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drm: refuse ADDFB2 ioctl for broken bigendian drivers

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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
This commit is contained in:
Gerd Hoffmann
2018-09-07 09:32:13 +02:00
parent ea4584c2f2
commit eae06120f1
3 changed files with 29 additions and 3 deletions
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24
drivers/gpu/drm/drm_framebuffer.c
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@@ -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;