Stefan Weil <s...@weilnetz.de> writes: > Am 29.07.2013 22:34, schrieb Andreas Färber: >> Am 29.07.2013 21:27, schrieb Stefan Weil: >>> Am 29.07.2013 20:55, schrieb Anthony Liguori: >>>> Stefan Weil <s...@weilnetz.de> writes: >>>> >>>>> Am 29.07.2013 20:05, schrieb Anthony Liguori: >>>>>> Stefan Weil <s...@weilnetz.de> 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 > > Maybe the problems only occur with TCG, but not with KVM. > That might explain why I get them more often than Anthony :-) > > Up to now, I did not try GTK terminals with KVM because my > typical test scenario uses MIPS or ARM boards on Intel hosts.
x86 vs. other will come into play too. The serial driver for x86 has some basic backoff logic. I suspect others don't. My guess why you don't see this on -serial stdio is that it probably is using synchronous I/O. Regards, Anthony Liguori > > Regards, > Stefan
