Re: [Qemu-devel] Re: Question about KVM and PC speaker

[Sebastian Herbszt]

Jan Kiszka wrote:
> Sebastian Herbszt wrote:
> > Jan Kiszka wrote:
> > > Sebastian Herbszt wrote:
> > > > Simon Bienlein wrote:
> > > > > Is a support for BIOS worked on right now?
> > > >
> > > > The vgabios (vgabios.c) has a "FIXME should beep". Volker, do you plan
> > > > to fix this?
> > > >
> > > > Which frequency should be used for the beep? Which delay?
> > >
> > > I would try 1 KHz and some hundred milliseconds.
> >
> > I just looked at some vga bios and it uses about 896,45 Hz.
> >
> > > > Getting a delay using "inb(0x61) & 0x10" is still a no go on qemu,
> > > > right?
> > >
> > > Looks like (should be far too inaccurate for longer delays). What about
> > > 0x40:0x6c, the BIOS' daily timer counter?
> >
> > The bios i looked at used the refresh request port 0x61. This is
> > supported by bochs and
> > there is also a patch for qemu to replace the dummy [1]. The rombios
> > uses this to provide
> > INT 15h AH=86h functionality; this is likely broken with the dummy code
> > in qemu.
>
> I see no problem with improving qemu's emulation accuracy this way a
> bit. But I wouldn't built new delay implementations on top of it,
> specifically if the code is in fact aware of running over a hypervisor.
> Such micro-timings are far too inaccurate for longer delays in an
> environment where you cannot be sure of running all the time during that
> period.

Volker, mind to resubmit the patch once again?

> > Anyway, using "timer ticks since midnight" should be possible (INT 08h
> > handler is set up
> > before vga bios is called).

I have implemented the beep for vgabios-6b and it works on bochs but fails on 
qemu.
With "-soundhw pcspk" i should hear it thru the hosts pc speaker, right?

- Sebastian