[alsa-devel] Alsa-lib strings?

[Takashi Iwai]

On Fri, 30 Sep 2016 09:50:57 +0200,
Clemens Ladisch wrote:
> 
> David Henningsson wrote:
> > 1a) can I count on alsa-lib's strings (everything from card name and
> >     mixer identifiers to various descriptions) to be UTF-8 or perhaps
> >     even 7-bit?
> 
> Alsa-lib itself does not care about the encoding.
> 
> The strings are whatever the kernel uses.  In practice, this almost
> always means ASCII, but kernel policy is UTF-8.  (At the moment, the
> only way I know of to get a non-ASCII string is from a USB device.)
> 
> Alsa-lib can also return strings from configuration files.  These are
> encoded in whatever the editor happens to use, i.e., in practice, UTF-8.
> 
> > 1b) In what way can buggy drivers violate the answers to 1a?
> 
> The USB driver is not buggy. :)  But in theory, you could get any random
> crap.
> 
> For testing, you can change a card's "id" attribute in sysfs.

The ID string should be OK, as it's filtered in
copy_valid_id_string().  But the other name strings have no checks,
thus may have non-ASCII letters (in theory).


Takashi