Hi Richard,
Richard Cochran <richardcoch...@gmail.com> writes: > On Tue, Jul 16, 2019 at 10:20:37AM +0300, Felipe Balbi wrote: >> When this new flag is set, we can use single-shot output. >> >> Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com> >> --- >> include/uapi/linux/ptp_clock.h | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h >> index 674db7de64f3..439cbdfc3d9b 100644 >> --- a/include/uapi/linux/ptp_clock.h >> +++ b/include/uapi/linux/ptp_clock.h >> @@ -67,7 +67,9 @@ struct ptp_perout_request { >> struct ptp_clock_time start; /* Absolute start time. */ >> struct ptp_clock_time period; /* Desired period, zero means disable. */ >> unsigned int index; /* Which channel to configure. */ >> - unsigned int flags; /* Reserved for future use. */ >> + >> +#define PTP_PEROUT_ONE_SHOT BIT(0) >> + unsigned int flags; /* Bit 0 -> oneshot output. */ >> unsigned int rsv[4]; /* Reserved for future use. */ > > Unfortunately, the code never checked that .flags and .rsv are zero, > and so the de-facto ABI makes extending these fields impossible. That > was my mistake from the beginning. > > In order to actually support extensions, you will first have to > introduce a new ioctl. No worries, I'll work on this after vacations (I'll off for 2 weeks starting next week). I thought about adding a new IOCTL until I saw that rsv field. Oh well :-) -- balbi