On Tue, Feb 03, 2009 at 08:41:14AM +0000, Mark Marshall wrote:
> Michael Tokarev wrote:
>> David S. Ahern wrote:
>>> Michael Tokarev wrote:
>>>> David S. Ahern wrote:
>>>>> I don't recall seeing a followup to this post.
>>>>>
>>>>> To put Michael's second suggestion into patch form, the following fixes
>>>>> the problem for me:
>>>>>
>>>>> --- kvm-81.orig/qemu/qemu-char.c 2008-12-14 06:16:27.000000000 -0700
>>>>> +++ kvm-81/qemu/qemu-char.c 2009-02-02 14:12:20.000000000 -0700
>>>>> @@ -1078,20 +1078,21 @@
>>>>> if (sarg | TIOCM_DTR)
>>>>> *targ |= CHR_TIOCM_DTR;
>>>>> if (sarg | TIOCM_RTS)
>>>>> *targ |= CHR_TIOCM_RTS;
>>>>> }
>>>>> break;
>>>>> case CHR_IOCTL_SERIAL_SET_TIOCM:
>>>>> {
>>>>> int sarg = *(int *)arg;
>>>>> int targ = 0;
>>>>> + ioctl(s->fd_in, TIOCMGET, &targ);
>>>> here, one more operation is necessary:
>>>> targ &= ~(TIOCM_DTR|TIOCM_RTS);
>>> Interesting. that change was not needed to fix my problem.
>>
>> It just means you (or, rather, your guests) never really needed to
>> DROP those signal lines, only to raise them.
>>
>>>>> if (sarg | CHR_TIOCM_DTR)
>>>>> targ |= TIOCM_DTR;
>>>>> if (sarg | CHR_TIOCM_RTS)
>>>>> targ |= TIOCM_RTS;
> Is this code really correct. If it is is there a comment somewhere
> describing why it's correct? I would have expected the lines above to
> be:
>
> if (sarg & CHR_TIOCM_DTR)
> targ |= TIOCM_DTR;
> if (sarg & CHR_TIOCM_RTS)
> targ |= TIOCM_RTS;
>
> (Just an observation as this went past).
Right. I don't understand the point of converting to an "internal"
representation of TIOCM control bits.
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:
{
- int sarg = 0;
- int *targ = (int *)arg;
- ioctl(s->fd_in, TIOCMGET, &sarg);
- *targ = 0;
- if (sarg | TIOCM_CTS)
- *targ |= CHR_TIOCM_CTS;
- if (sarg | TIOCM_CAR)
- *targ |= CHR_TIOCM_CAR;
- if (sarg | TIOCM_DSR)
- *targ |= CHR_TIOCM_DSR;
- if (sarg | TIOCM_RI)
- *targ |= CHR_TIOCM_RI;
- if (sarg | TIOCM_DTR)
- *targ |= CHR_TIOCM_DTR;
- if (sarg | TIOCM_RTS)
- *targ |= CHR_TIOCM_RTS;
+ ioctl(s->fd_in, TIOCMGET, arg);
}
break;
case CHR_IOCTL_SERIAL_SET_TIOCM:
{
- int sarg = *(int *)arg;
- int targ = 0;
- if (sarg | CHR_TIOCM_DTR)
- targ |= TIOCM_DTR;
- if (sarg | CHR_TIOCM_RTS)
- targ |= TIOCM_RTS;
- ioctl(s->fd_in, TIOCMSET, &targ);
+ ioctl(s->fd_in, TIOCMSET, arg);
}
break;
default:
--
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