Hi Rob,
On Thu, Jan 12, 2017 at 6:27 PM, Rob Herring <r...@kernel.org> wrote:
> I just noticed that we have a new device attribute 'deferred_probe'
> added in 4.10 with this commit:
>
> commit 6751667a29d6fd64afb9ce30567ad616b68ed789
> Author: Ben Hutchings <ben.hutchi...@codethink.co.uk>
> Date: Tue Aug 16 14:34:18 2016 +0100
>
> driver core: Add deferred_probe attribute to devices in sysfs
>
> It is sometimes useful to know that a device is on the deferred probe
> list rather than, say, not having a driver available. Expose this
> information to user-space.
>
> Signed-off-by: Ben Hutchings <ben.hutchi...@codethink.co.uk>
> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
>
>
> It seems like a bad idea to add an ABI for an internal kernel feature.
> When/if we replace deferred probe with something better based on
> functional dependencies are we going to keep this attr around? Or
> remove it and assume no userspace uses it? Perhaps it should be hidden
> behind CONFIG_DEBUG or just make a debugfs file that lists the
> deferred list. Then you wouldn't have to hunt for what got deferred.
FWIW, I had just created a "check-deferred-probe" script that does
find /sys -name deferred_probe -print0 | xargs -0 grep -v '^0$'
A list would be even better, from the point of view of the user.
As I haven't looked at the implementation, I don't know what impact
that would have on the system due to e.g. locking.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
