[Qemu-devel] [RFC] 2nd serial port by default

[Qemu-devel] [RFC] 2nd serial port by default

[Hervé Poussineau]

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Hi,

Most computers have 0 or 2 serial ports, but Qemu only allocates one by 
default.
Attached patch defines 2 serial ports by default, instead of one.
Previous behaviour can be done with "-serial vc:80Cx24C -serial none" 
argument.

Please comment

Hervé

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Re: [Qemu-devel] [RFC] 2nd serial port by default

[Paul Brook]

On Sunday 07 December 2008, Hervé Poussineau wrote:
> Hi,
>
> Most computers have 0 or 2 serial ports, but Qemu only allocates one by
> default.
> Attached patch defines 2 serial ports by default, instead of one.
> Previous behaviour can be done with "-serial vc:80Cx24C -serial none"
> argument.
>
> Please comment

I'm not sure where you're getting "most" from, or your justification for this 
change.

A quick survey here indicates that most workstation/server class hardware has 
a single accessible serial port, and embedded boards commonly have 3 or 4.

In practice I'd expect that by far the most common use for serial ports is a 
serial console, and one is more than sufficient for that. If you want to do 
anything else then you're probably going to need special -serial options 
anyway.

Paul

Re: [Qemu-devel] [RFC] 2nd serial port by default

[Stuart Brady]

On Mon, Dec 08, 2008 at 12:26:40PM +0000, Paul Brook wrote:
> In practice I'd expect that by far the most common use for serial ports is a 
> serial console, and one is more than sufficient for that. If you want to do 
> anything else then you're probably going to need special -serial options 
> anyway.

The issue here is that the MIPS Magnum has two serial ports, and its
firmware checks that both serial ports are functioning and complains
if either of them is not.  If the user only needs a single serial port,
then they currently have to pass '-serial null' for the second port.

IMO, the default number of ports that are emulated should depend on the
machine that is being emulated.

Cheers,
-- 
Stuart Brady