Messages in this thread | | | Date | Fri, 09 May 2014 14:20:45 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports |
| |
On 05/09/2014 02:12 PM, Arnd Bergmann wrote: > >> However, if we're going to have these devices I'm wondering if having >> /dev/portw and /dev/portl (or something like that) might not make sense, >> rather than requiring a system call per transaction. > > Actually the behavior of /dev/port for >1 byte writes seems questionable > already: There are very few devices on which writing to consecutive > port numbers makes sense. Normally you just want to write a series > of bytes (or 16/32 bit words) into the same port number instead, > as the outsb()/outsw()/outsl() functions do. >
Indeed. I missed the detail that it increments the port index; it is virtually guaranteed to be bogus.
-hpa
| |