From 43e3433a48c303b9dac1e72cd7eebce0be1e2cb3 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 13 Jun 2025 20:47:49 +0300 Subject: [PATCH] ptp: allow reading of currently dialed frequency to succeed on free-running clocks [ Upstream commit aa112cbc5f0ac6f3b44d829005bf34005d9fe9bb ] There is a bug in ptp_clock_adjtime() which makes it refuse the operation even if we just want to read the current clock dialed frequency, not modify anything (tx->modes == 0). That should be possible even if the clock is free-running. For context, the kernel UAPI is the same for getting and setting the frequency of a POSIX clock. For example, ptp4l errors out at clock_create() -> clockadj_get_freq() -> clock_adjtime() time, when it should logically only have failed on actual adjustments to the clock, aka if the clock was configured as slave. But in master mode it should work. This was discovered when examining the issue described in the previous commit, where ptp_clock_freerun() returned true despite n_vclocks being zero. Fixes: 73f37068d540 ("ptp: support ptp physical/virtual clocks conversion") Signed-off-by: Vladimir Oltean Link: https://patch.msgid.link/20250613174749.406826-3-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/ptp/ptp_clock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c index 6b7e8b7ebcef..b7fc260ed43b 100644 --- a/drivers/ptp/ptp_clock.c +++ b/drivers/ptp/ptp_clock.c @@ -104,7 +104,8 @@ static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx) struct ptp_clock_info *ops; int err = -EOPNOTSUPP; - if (ptp_clock_freerun(ptp)) { + if (tx->modes & (ADJ_SETOFFSET | ADJ_FREQUENCY | ADJ_OFFSET) && + ptp_clock_freerun(ptp)) { pr_err("ptp: physical clock is free running\n"); return -EBUSY; }