Re: [PATCH 3/6] drm: fourcc byteorder: add bigendian support to drm_mode_legacy_fb_format

[Michel DÃnzer]

On 24/04/17 03:25 PM, Gerd Hoffmann wrote:
> Return correct fourcc codes on bigendian.  Drivers must be adapted to
> this change.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>

Just to reiterate, this won't work for the radeon driver, which programs
the GPU to use (effectively, per the current definition that these are
little endian GPU formats) DRM_FORMAT_XRGB8888 with pre-R600 and
DRM_FORMAT_BGRX8888 with >= R600.


> +#ifdef __BIG_ENDIAN
> +	switch (bpp) {
> +	case 8:
> +		fmt = DRM_FORMAT_C8;
> +		break;
> +	case 24:
> +		fmt = DRM_FORMAT_BGR888;
> +		break;

BTW, endianness as a concept cannot apply to 8 or 24 bpp formats.


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Earthling Michel DÃnzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer