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

[Andreas Färber]

Am 29.07.2013 21:27, schrieb 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.

FWIW I've been seeing similar garbled-Gtk-output issues on openSUSE 12.3
but didn't investigate further. -monitor stdio has so far not failed me
on the same system by comparison.

One reproducible test case was the openrisc kernel that Jia provided
recently.

Regards,
Andreas

> 
> 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
> 
> 


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