Re: [Qemu-devel] [BUG] GTK terminal is broken

[Stefan Weil]

Am 29.07.2013 20:55, schrieb Anthony Liguori:
> Stefan Weil <address@hidden> writes:
>
>> Am 29.07.2013 20:05, schrieb Anthony Liguori:
>>> Stefan Weil <address@hidden> writes:
>>>
>>>> Hello,
>>>>
>>>> maybe most developers will already have noticed that the terminal output
>>>> in QEMU's GTK user interface is broken. As far as I know, it never worked,
>>>> but as there are working alternatives, I did not care much and forgot to
>>>> report the issues.
>>>>
>>>> See these snapshots which show the problems with QEMU's GTK terminals:
>>>>
>>>> http://qemu.weilnetz.de/test/bugs/qemu-gtk-demo1.png
>>>>
>>>> Here the first line of the QEMUmonitor is only partially visible.
>>>> Tested with Cygwin/X on W64 host, QEMU running on Debian Linux.
>>>> Other X servers (e.g. native X on Debian Linux) don't show this
>>>> problem.
>>> It's a GTK/Cygwin/X bug.
>>>
>>> We use a vbox without anything particularly fancy happening.  Looks like
>>> something is calculating layout incorrectly.
>>>
>>> Regards,
>>>
>>> Anthony Liguori
>> I miss a comment on the more important next two points.
>> They are _not_ related to Cygwin / X.
>>
>> Do you investigate them?
> What you're seeing has always existed and is not GTK specific.  There is
> not flow control on the outgoing side of serial emulation.  Data will
> get dropped.
>
> My guess is that your system is sufficiently slow and overloaded that
> it's happening a lot for you.
>
> Regards,
>
> Anthony Liguori

If it were as simply as that, that would be fine, but alas,
it isn't. Even fast servers without any load show dropped
characters. There are dropped characters for QEMU's
monitor window (Alt-ctrl-2) and for Malta's line display
(Alt-Ctrl-5). Neither of these two should suffer from missing
flow control.

And even a current X.Org on Ubuntu shows the first bug
(crippled first line) here, so it is not Cygwin / X specific.

None of the Linux hosts which I use in my test is able
to display a correct Linux boot protocol on QEMU's
GTK serial console window. All of them work with SDL
or when the serial console is redirected to stdout.

Regards,

Stefan Weil