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Date: Fri, 14 Dec 2012 15:05:13 +0100
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/3] chardev: add hotplug support.
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org

On 12/14/12 14:45, Paolo Bonzini wrote:
> Il 14/12/2012 14:18, Gerd Hoffmann ha scritto:
>>   Hi,
>>
>>> { 'enum': 'ChardevFileMode', 'data':
>>>   # pty = console under Windows
>>>   # serial = tty under POSIX
>>>   [ 'file', 'pipe', 'parport', 'pty', 'serial' ] }
>>
>> Hmm, why this enum?  I'd stay close to -chardev, i.e. specify the type
>> by backend name.
> 
> Because...
> 
>>> { 'enum: 'ChardevFileSource', 'data':
>>>   [ 'path', 'fd' ] }
>>
>> I guess I'd just create a new backend type for file descriptor passing
>> instead of fitting that into all the existing ones.
> 
> ... are you passing a file descriptor for a pipe, a file or a
> parallel/serial port?

The open function of the file-based backends basically do (1) create
file handles and (2) call qemu_chr_open_fd().  So of you already have an
fd the differences are gone.  Well, almost.  tty has an special ioctl
callback to configure line speed.

cheers,
  Gerd