On Fri, Oct 11, 2024, at 09:53, Andy Shevchenko wrote: > On Fri, Oct 11, 2024 at 06:18:18AM +0000, Arnd Bergmann wrote: > > ... > >> + if (!IS_ENABLED(CONFIG_HAS_IOPORT)) { >> + *value = BIT_MASK(width); >> + return AE_NOT_IMPLEMENTED; > > Perhaps it has already been discussed, but why do we need to file value with > semi-garbage when we know it's invalid anyway? It's not strictly necessary, just precaution for possible callers that use the resulting data without checking the error code. The all-ones data is what an x86 PC would see when an I/O port is read that is not connected to any device. Arnd