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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , John Stultz , Thomas Gleixner , Stephen Boyd , Miroslav Lichvar , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alexander Gordeev Cc: David Woodhouse Subject: [PATCH v4 2/4] pps: Drop the !NO_HZ_COMMON dependency from NTP_PPS Date: Sat, 29 Aug 2026 21:57:00 +0100 Message-ID: <20260829210041.40649-3-dwmw2@infradead.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260829210041.40649-1-dwmw2@infradead.org> References: <20260829210041.40649-1-dwmw2@infradead.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html From: David Woodhouse NTP_PPS has been disabled for tickless kernels since it was first introduced in commit 025b40abe715d ("ntp: add hardpps implementation") in 2011, with a comment that it "doesn't work on tickless kernels at the moment". Whatever the original reasons were, the only *remaining* reason seems to have been that the accuracy of the time captured by pps_get_ts() was poor on tickless kernels due to the kernel's per-tick timekeeping mechanism. A recent change to ktime_get_snapshot_id() which is used by pps_get_ts() has fixed that problem, by applying a correction to the ::systime field so that it reports the ideal NTP-corrected time rather than the sanitized and smoothed version which varies each tick. Drop the no longer needed dependency. Signed-off-by: David Woodhouse Assisted-by: Kiro:claude-opus-4.8 --- drivers/pps/Kconfig | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig index e1651d51cfc9..3a2c457ed9d8 100644 --- a/drivers/pps/Kconfig +++ b/drivers/pps/Kconfig @@ -31,13 +31,10 @@ config PPS_DEBUG config NTP_PPS bool "PPS kernel consumer support" - depends on !NO_HZ_COMMON help This option adds support for direct in-kernel time synchronization using an external PPS signal. - It doesn't work on tickless systems at the moment. - source "drivers/pps/clients/Kconfig" source "drivers/pps/generators/Kconfig" -- 2.55.0