Re: [PATCH 2/2] ptp: ptp_s390: Add missing facility check
From: Heiko Carstens <hca@linux.ibm.com>
Date: 2026-07-14 09:39:16
Also in:
linux-s390, lkml
On Tue, Jul 14, 2026 at 10:49:21AM +0200, Sven Schnelle wrote:
quoted hunk ↗ jump to hunk
Only register the physical clock when facility 28 is installed. Fixes: 2d7de7a3010d ("s390/time: Add PtP driver") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Cc: stable@kernel.org --- drivers/ptp/ptp_s390.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)diff --git a/drivers/ptp/ptp_s390.c b/drivers/ptp/ptp_s390.c index 7299c3aae65f..3ea94648cdde 100644 --- a/drivers/ptp/ptp_s390.c +++ b/drivers/ptp/ptp_s390.c@@ -108,6 +108,9 @@ static __init int ptp_s390_init(void) if (IS_ERR(ptp_stcke_clock)) return PTR_ERR(ptp_stcke_clock); + if (!test_facility(28)) + return 0; + ptp_qpt_clock = ptp_clock_register(&ptp_s390_qpt_info, NULL); if (IS_ERR(ptp_qpt_clock)) { ptp_clock_unregister(ptp_stcke_clock);
Wouldn't it make more sense to check if PTFF-QPT is available via PTFF-QAF before registering the clock? This would also avoid the need of the first patch - since then it is guaranteed that PTFF-QPT will always return with condition code zero. And... we wouldn't have the potential oddity to have a clock registered which doesn't work.