On Thu, 31 Jul 2025, Christophe Leroy wrote: > > > Le 31/07/2025 à 16:35, Christophe Leroy a écrit : > > Hi Jiri, > > > > Le 11/06/2025 à 12:02, Jiri Slaby (SUSE) a écrit : > >> _IO*() is the proper way of defining ioctl numbers. All these vt numbers > >> were synthetically built up the same way the _IO() macro does. > >> > >> So instead of implicit hex numbers, use _IO() properly. > >> > >> To not change the pre-existing numbers, use only _IO() (and not _IOR() > >> or _IOW()). The latter would change the numbers indeed. > > > > On powerpc your assumption is wrong, because _IOC_NONE is not 0: > > > > $ git grep _IOC_NONE arch/powerpc/ > > arch/powerpc/include/uapi/asm/ioctl.h:#define _IOC_NONE 1U > > > > Therefore the value changes even with _IO(), leading to failure of Xorg as > > reported by Christian. > > > > And is likely an issue on the 4 following architectures: > > $ git grep _IOC_NONE arch/ | grep 1U > arch/alpha/include/uapi/asm/ioctl.h:#define _IOC_NONE 1U > arch/mips/include/uapi/asm/ioctl.h:#define _IOC_NONE 1U > arch/powerpc/include/uapi/asm/ioctl.h:#define _IOC_NONE 1U > arch/sparc/include/uapi/asm/ioctl.h:#define _IOC_NONE 1U
IMHO this one patch could simply be reverted and the "old" code let be. Nicolas
