Re: [Qemu-devel] [PATCH 3/4] Add support for HPET periodic timer.

Matthew Kent
2007-08-21T19:24:05Z

On Sat, 2007-18-08 at 01:11 +0200, Luca Tettamanti wrote:
> plain text document attachment (clock-hpet)
> Linux operates the HPET timer in legacy replacement mode, which means that
> the periodic interrupt of the CMOS RTC is not delivered (qemu won't be able
> to use /dev/rtc). Add support for HPET (/dev/hpet) as a replacement for the
> RTC; the periodic interrupt is delivered via SIGIO and is handled in the
> same way as the RTC timer.
>
> Signed-off-by: Luca Tettamanti <kronos.it-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

I must be missing something silly here.. should I be able to open more
than one instance of qemu with -clock hpet? Because upon invoking a
second instance of qemu HPET_IE_ON fails.

I also tried running the example in the kernel docs under
Documentation/hpet.txt

mkent@localhost [/home/mkent]# ./demo poll /dev/hpet 1 1000
-hpet: executing poll
hpet_poll: info.hi_flags 0x0
hpet_poll: expired time = 0x8
hpet_poll: revents = 0x1
hpet_poll: data 0x1

<in another term>
mkent@localhost [/home/mkent]# ./demo poll /dev/hpet 1 1000
-hpet: executing poll
hpet_poll: info.hi_flags 0x0
hpet_poll, HPET_IE_ON failed

This is on 2.6.23-rc3 x86_64 with the patch-2.6.23-rc3-hrt2.patch
hrtimers patch.
--
Matthew Kent <mkent-rTVjrLRGJfNWk0Htik3J/w@public.gmane.org>