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

[Jan Kiszka]

Samuel Thibault wrote:
> Jan Kiszka, le Thu 23 Apr 2009 09:45:17 +0200, a écrit :
>> Simon Bienlein wrote:
>>> I hear the beep if I am in the bash of the wirtsystem and press the
>>> backspace key on the start of the line. The PC speaker works therefore.
>>>
>>> How can I configure KVM so that the PC speaker also works in the VM?
>>> Supports the BIOS PC Speaker beeps?
>> Nope, not yet. Neither QEMU nor KVM (with its in-kernel handling of the
>> involved timer chip) translates the guest's speaker settings into
>> anything audible. But that should be feasible.
> 
> Err, have you read the first paragraph?  The speaker does work.

Misunderstanding: "Wirt" means host in English. So it works on his host
system, but not inside the guest. And that's consistent with QEMU code:
there is no handling of port 0x61 in user space, only dummy code in the
KVM kernel part, and no one bother about the counter value of PIT
channel 2 (which defines the beeper frequency).

> 
>>> The environment variable QEMU_AUDIO_DRV=alsa is set and I run KVM with
>>> the option -soundhw all.
>> You may succeed with this approach when redirecting the guest's console
>> beep to the sound card of your virtual machine.
> 
> The problem is not the guest's console beep: as mentioned above, that
> one does work. The one that doesn't is the syslinux beep of the debian
> installer CD, which is supposed to be implemented in the bios.

Doing beep via the BIOS is surely another to-do, and a useful hint in
this context. But unless you add a paravirt firmware beep channel or
BIOS support for sound cards or, and that' probably the best approach,
PC speaker emulation, how should the beep be emitted?

Jan

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