Re: [PATCH 1/1] clock_getres.2: dynamic POSIX clock devices can return other errors

[Eric Rannaud <eric.rannaud@gmail.com>]

Micheal,

I'm conscious that saying "dynamic POSIX clock device" without any
explanation may be too obscure for a man page.

There is documentation in:
- include/linux/posix-clock.h
- Documentation/driver-api/ptp.rst (explicitly states that EOPNOTSUPP
should be returned)
- include/uapi/linux/ptp_clock.h

(IEEE 1588 PTP is the canonical user of these dynamic clock devices)

Would you want to refer to any of these from the man page?

Thanks for maintaining this project!
Eric

On Thu, Apr 2, 2020 at 7:24 AM Eric Rannaud <e@nanocritical.com> wrote:
>
> See Linux source as of v5.4:
>   kernel/time/posix-clock.c
>
> Signed-off-by: Eric Rannaud <e@nanocritical.com>
> ---
>  man2/clock_getres.2 | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/man2/clock_getres.2 b/man2/clock_getres.2
> index 0154f9d32473..71f7f8dfa662 100644
> --- a/man2/clock_getres.2
> +++ b/man2/clock_getres.2
> @@ -260,6 +260,10 @@ specified in a call to
>  .BR clock_settime ()
>  is not a settable clock.
>  .TP
> +.B EOPNOTSUPP
> +The operation is not supported by the dynamic POSIX clock device
> +specified.
> +.TP
>  .BR EINVAL " (since Linux 4.3)"
>  .\" commit e1d7ba8735551ed79c7a0463a042353574b96da3
>  A call to
> @@ -276,6 +280,11 @@ clock.
>  .B EPERM
>  .BR clock_settime ()
>  does not have permission to set the clock indicated.
> +.TP
> +.B EACCES
> +.BR clock_settime ()
> +does not have write permission for the dynamic POSIX
> +clock device indicated.
>  .SH VERSIONS
>  These system calls first appeared in Linux 2.6.
>  .SH ATTRIBUTES
> --
> 2.26.0
>