libpciaccess and users depending on the revision field

[Adam Jackson]

On Wed, 2016-11-02 at 13:00 +0000, Emil Velikov wrote:

> Gist:
> The kernel does not expose separate file for the revision field, yet
> there's a [freshly sent] kernel patch to address that.
> Thus libpciaccess's reads through the config file and wakes up the
> device, which we want to avoid where possible.
> 
> Question is - can we cheat [and return 0/-1] if the kernel does not
> create the file or should we fall-back to reading the config.

You should fall back. That field definitely has real meaning for many
of the older UMS drivers (from a quick grep, at least: ast, geode,
mach64, mga, s3, sis and tseng).

- ajax