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Re: [Qemu-devel] [PATCH v2] stop using stdio for monitor/serial/etc with
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-devel] [PATCH v2] stop using stdio for monitor/serial/etc with -daemonize |
Date: |
Wed, 26 Sep 2012 12:17:39 +0400 |
User-agent: |
Mozilla/5.0 (X11; Linux i686 on x86_64; rv:10.0.6esrpre) Gecko/20120817 Icedove/10.0.6 |
On 26.09.2012 12:00, Peter Maydell wrote:
>> I know lots of people use -nographic -daemonize to run headless
>> guests in background (like, for example, a router). I guess it
>> come way before -vga option has been introduced, but at least I
>> know about -vga (but not about -vga none). For one, I never saw
>> -display before. And it looks like -nographic is a synonym for
>> -display none, and -curses is a synonym for -display curses.
I mean, -nographic is about the same as -vga none -display none.
> -nographic does about three different things at once (and I think
> some of its effects aren't documented). It's a legacy option retained
> for backward compatibility with old command lines.
Sure. Just like, for example, -stdvga was at the time being.
> If you want something that is non-confusing and makes sense, then
> use -display none to disable graphics, -serial stdio to send serial
> to stdio, and so on. These newer options do one clear thing each
> and can be combined straightforwardly.
>
>> It looks like we have way too many confusing options doing the
>> same thing. And I think they should be consistent, at least
>> when they SMELL like they do the same thing, instead of forbidding
>> one or another in some situations.
>
> I'd love to drop -nographic but we'd break huge numbers of
> existing setups...
So let's make it actually work as expected till we're able to finally
drop it.
What is equivalent of -nographic in terms of -vga/-display/-...?
>From the code it is something like
-vga none -display none -serial mon:stdio -parallel null
(this is the code I tried to patch).
Note: this, compbined with -daemonize, also has the same issue,
namely, the tty is left in a bad state after qemu process backgrounded,
and for the very same reason: -serial stdio switches the try into
raw mode. So this should be fixed too -- somehow, either by forbidding
this combination completely or by silently substituting stdio for
-serial with null. But it will be done in a subsequent patch.
Note also: by forbidding -nographic -daemonize, we'll break lots of
existing setups too, and I still don't see why this combination is
bad, I already demonstrated that it can be made to work in a more
or less reasonable/expected way.
Thanks,
/mjt