Messages in this thread | | | Subject | Re: [PATCH 3/6] drm: fourcc byteorder: add bigendian support to drm_mode_legacy_fb_format | From | Michel Dänzer <> | Date | Thu, 27 Apr 2017 09:52:59 +0900 |
| |
On 26/04/17 09:11 PM, Gerd Hoffmann wrote: > Hi, > >>>> 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. >>> >>> Hmm, ok, how does bigendian fbdev emulation work on pre-R600 then? >> >> Using a GPU byte swapping mechanism which only affects CPU access to >> video RAM. > > That is done using the RADEON_TILING_SWAP_{16,32}BIT flag mentioned in > another thread?
Right.
> What about dumb bos? You've mentioned the swap flag isn't used for > those. Which implies they are in little endian byte order (both gpu and > cpu view).
Right, AFAICT from looking at the code.
> Does the modesetting driver work correctly on that hardware?
Not sure.
-- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
| |