On Thursday, 23 October 2025 at 06:45, Nick Bowler nbowler@draconx.ca wrote:
After a stable kernel update, the hwclock command seems no longer functional on my SPARC system with an ST M48T59Y-70PC1 RTC:
# hwclock [...long delay...]
I assume this is 10 seconds long.
hwclock: select() to /dev/rtc0 to wait for clock tick timed out
And this is 100% reproducible, or does it sometimes work and sometimes fail?
On prior kernels, there is no problem:
# hwclock 2025-10-22 22:21:04.806992-04:00
I reproduced the same failure on 6.18-rc2 and bisected to this commit:
commit 795cda8338eab036013314dbc0b04aae728880ab Author: Esben Haabendal esben@geanix.com
Date: Fri May 16 09:23:35 2025 +0200
rtc: interface: Fix long-standing race when setting alarm
This commit was backported to all current 6.x stable branches, as well as 5.15.x, so they all have the same regression.
Reverting this commit on top of 6.18-rc2 corrects the problem.
Let me know if you need any more info!
Are you using the util-linux hwclock command? Which version?
Do you have CONFIG_RTC_INTF_DEV_UIE_EMUL enabled?
Can you run `hwclock --verbose`, both with and without the reverted commit, and send the output from that?
/Esben