[PATCH v2] drm: refuse ADDFB2 ioctl for broken bigendian drivers

[kbuild test robot]

Hi Gerd,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.19-rc2 next-20180906]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Gerd-Hoffmann/drm-refuse-ADDFB2-ioctl-for-broken-bigendian-drivers/20180910-142802
config: xtensa-allmodconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 8.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=8.1.0 make.cross ARCH=xtensa 

All errors (new ones prefixed by >>):

   drivers/gpu//drm/drm_framebuffer.c: In function 'drm_mode_addfb2_ioctl':
>> drivers/gpu//drm/drm_framebuffer.c:359:23: error: 'struct drm_mode_config' has no member named 'quirk_addfb_prefer_host_byte_order'
     if (!dev->mode_config.quirk_addfb_prefer_host_byte_order) {
                          ^

vim +359 drivers/gpu//drm/drm_framebuffer.c

   354	
   355	int drm_mode_addfb2_ioctl(struct drm_device *dev,
   356				  void *data, struct drm_file *file_priv)
   357	{
   358	#ifdef __BIG_ENDIAN
 > 359		if (!dev->mode_config.quirk_addfb_prefer_host_byte_order) {
   360			/*
   361			 * Drivers must set the
   362			 * quirk_addfb_prefer_host_byte_order quirk to make
   363			 * the drm_mode_addfb() compat code work correctly on
   364			 * bigendian machines.
   365			 *
   366			 * If they don't they interpret pixel_format values
   367			 * incorrectly for bug compatibility, which in turn
   368			 * implies the ADDFB2 ioctl does not work correctly
   369			 * then.  So block it to make userspace fallback to
   370			 * ADDFB.
   371			 */
   372			DRM_DEBUG_KMS("addfb2 broken on bigendian");
   373			return -EINVAL;
   374		}
   375	#endif
   376		return drm_mode_addfb2(dev, data, file_priv);
   377	}
   378	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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