[Qemu-devel] Re: more about serial ports: do they even work?

[Marcelo Tosatti <mtosatti@redhat.com>]

On Wed, Feb 04, 2009 at 11:37:14AM +0300, Michael Tokarev wrote:
> Marcelo Tosatti wrote:
> > On Tue, Feb 03, 2009 at 08:41:14AM +0000, Mark Marshall wrote:
> []
> > Right. I don't understand the point of converting to an "internal"
> > representation of TIOCM control bits. 
> 
> <fun mode>
> Well, the same goes for the IOCTL values themselves too -- like
> this CHR_IOCTL_SERIAL_SET_TIOCM itself.  I mean, TIOCMSET is
> the right name for it ;)  But see below.
> 
> > CHR_IOCTL_SERIAL_SET_TIOCM is clearly broken as mentioned. It should at 
> > least preserve the bits it does not control.
> > 
> > diff --git a/qemu/qemu-char.c b/qemu/qemu-char.c
> > index ac431c7..66971e1 100644
> > --- a/qemu/qemu-char.c
> > +++ b/qemu/qemu-char.c
> > @@ -1063,33 +1063,12 @@ static int tty_serial_ioctl(CharDriverState *chr, int cmd, void *arg)
> >          break;
> >      case CHR_IOCTL_SERIAL_GET_TIOCM:
> >          {
> > +            ioctl(s->fd_in, TIOCMGET, arg);
> >          }
> >          break;
> 
> And those parens too, let it die, die! ;)

Kill it!

> </fun mode>
> 
> Other than that, an.. excellent idea, I wanted to propose
> just that when I first saw all this stuff, but was somewhat
> afraid.  And I *think* there's at least *some* sense.  Qemu
> is a CPU emulator and may work on another arch where those
> bits are defined differently.  Maybe that was the reason for
> all this converting - to be safe than sorry, so to say.  No?

Probably, yes.

Does it work for you?