On Wed, Dec 14, 2016 at 4:31 PM, Seth Forshee <seth.forshee...@canonical.com > wrote:
> Looking at kernel 4.9, the RTC_UIE_ON ioctl sets an alarm via the > cmos_rtc driver. This does a couple of things. > > 1. Disables the CMOS RTC alarm interrupt, writes an alarm time to the > CMOS RTC, then enables the alarm interrupt. > > 2. When configured to emulate an RTC using the HPET (which our kernel > is), makes sure HPET timer 1 is initialized for RTC emulation. > > Based on this I looked at the diffs for hw/timer/mc146818rtc.c (which > seems to be the CMOS RTC device) and hw/timer/hpet.c between the two > qemu versions. The differences all look pretty trivial, I don't see > anything which looks like it would have fixed the problem. > It's a guest kernel + qemu interaction. In the past, there was an issue w.r.t ensuring RTC interrupts were being delivered; that's what's currently broken. Comparing: grep rtc /proc/interrupts where it works (Trusty) vs failed, and you can see that we get at most a few interrupts to the RTC device. There isn't a whole lot of change to qemu's RTC between 2.5 and 2.6.1 in yakkety So, I need to see if running yakkety qemu on Xenial fixes things as well so we can continue to narrow down where the regression was introduced. > > -- > You received this bug notification because you are subscribed to qemu in > Ubuntu. > https://bugs.launchpad.net/bugs/1649718 > > Title: > Linux rtc self test fails in a VM under xenial > > To manage notifications about this bug go to: > https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1649718/+subscriptions > -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1649718 Title: Linux rtc self test fails in a VM under xenial To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1649718/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
