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Message-ID: <49F0A876.4050902@siemens.com>
Date: Thu, 23 Apr 2009 19:42:14 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: Re: [Qemu-devel] Re: Question about KVM and PC speaker
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To: Avi Kivity <avi@redhat.com>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>, Qemu-devel@nongnu.org, kvm-devel <kvm@vger.kernel.org>, Simon Bienlein <s.bienlein@gmx.de>

Avi Kivity wrote:
> Jan Kiszka wrote:
>> Avi Kivity wrote:
>>  
>>> Jan Kiszka wrote:
>>>    
>>>> Huh, it is! Then the problem is a KVM-only thing: The kernel part hooks
>>>> onto those resources but doesn't communicate changes to this user space
>>>> backend.
>>>>         
>>> In this case, the -no-kvm-pit option should help.
>>>     
>>
>> Probably fine in many cases (where the PIT is no longer used anyway),
>> just a bit unintuitive for users.
>>   
> 
> Yes, it's only a workaround.
> 
>> I wonder why KVM moved port 0x61 handling into kernel space at all. By
>> leaving it in pcspk hands and extending the latter to sync with the
>> in-kernel PIT on sample generation, this speaker regression (of
>> kvm-userspace) should have been avoidable.
>>   
> 
> I'd rather not have partial components in the kernel.  This case is
> particularly icky though.

But you surely don't want to issue the sound from kernel space.
Moreover, these are separate components: the PIT doesn't bother about
the speaker, if it's on or off. We just need to make pcspk KVM-aware. I
think I will post a patch later today.

Jan

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