On Fri, Apr 21, 2017 at 11:50:18AM +0200, Gerd Hoffmann wrote: > On Fr, 2017-04-21 at 12:25 +0300, Ville Syrjälä wrote: > > On Fri, Apr 21, 2017 at 09:58:24AM +0200, Gerd Hoffmann wrote: > > > While working on graphics support for virtual machines on ppc64 (which > > > exists in both little and big endian variants) I've figured the comments > > > for various drm fourcc formats in the header file don't match reality. > > > > > > Comments says the RGB formats are little endian, but in practice they > > > are native endian. Look at the drm_mode_legacy_fb_format() helper. It > > > maps -- for example -- bpp/depth 32/24 to DRM_FORMAT_XRGB8888, no matter > > > whenever the machine is little endian or big endian. The users of this > > > function (fbdev emulation, DRM_IOCTL_MODE_ADDFB) expect the framebuffer > > > is native endian, not little endian. Most userspace also operates on > > > native endian only. > > > > I'm not a fan of "native". Native to what? "CPU" or "host" is what I'd > > call it. > > native == whatever the cpu is using. > > I personally find "native" more intuitive, but at the end of the day I > don't mind much. If people prefer "host" over "native" I'll change it. > > > And what about the mxied endian case? Are you just going to pretend it > > doesn't exist or what? > > What exactly do you mean with "mixed endian"? The powerpc case, where > kernel + userspace can run in either big or little endian mode? Or > something else? Big endian CPU and little endian GPU. I think that should be the most common case these days. -- Ville Syrjälä Intel OTC
