On Sat, 18 Dec 2021, Dan Ritter wrote:
Greg Wooledge wrote:Today I rebooted my machine for the first time in quite a while, after the kernel update that was released along with Debian 11.2....Eventually, after a minute or two, the system booted. Everything is working normally now, post-GRUB.I upgraded three machines to that kernel, today. Two of them went smoothly. One of them took a ridiculously long time to boot. I suspect it is some interesting interaction specific to machine quirks and this release and/or kernel.
The problem, as described, is during the grub countdown. It hasn't even committed to booting a particular OS at this point, let alone a particular kernel version. I don't know how grub does its timings. Does the motherboard use a coin cell battery backup RTC and the battery is completely dead leading to bad calibration? But I'm making wild guesses with absolutely no knowledge of how grub works under the hood. Check if the kernel log jumps from 1/1/70 to today as it boots. That would point to the RTC being bad when the kernel first starts.