serial hang in qemu-system-ppc64 -M pseries

[Thomas Huth]

On 27/04/2022 17.27, Thomas Huth wrote:
> On 26/04/2022 12.26, Rob Landley wrote:
>> When I cut and paste 80-ish characters of text into the Linux serial 
>> console, it
>> reads 16 characters and stops. When I hit space, it reads another 16 
>> characters,
>> and if I keep at it will eventually catch up without losing data. If I type,
>> every character shows up immediately.
> 
> That "16" certainly comes from VTERM_BUFSIZE in hw/char/spapr_vty.c in the 
> QEMU sources, I think.
> 
>> (On other qemu targets and kernels I can cut and paste an entire uuencoded
>> binary and it goes through just fine in one go, but this target hangs with 
>> big
>> pastes until I hit keys.)
>>
>> Is this a qemu-side bug, or a kernel-side bug?
>>
>> Kernel config attached (linux 5.18-rc3 or thereabouts), qemu invocation is:
>>
>> qemu-system-ppc64 -M pseries -vga none -nographic -no-reboot -m 256 -kernel
>> vmlinux -initrd powerpc64leroot.cpio.gz -append "panic=1 HOST=powerpc64le
>> console=hvc0"
> 
> Which version of QEMU are you using? Which frontend (GTK or terminal?) ... 
> this rings a distant bell, but I thought we had fixed these issues long ago 
> in the past... e.g.:
> 
> https://yhbt.net/lore/all/1380113886-16845-10-git-send-email-mdroth@linux.vnet.ibm.com/ 
> 
> https://git.qemu.org/?p=qemu.git;a=commitdiff;h=8a273cbe53221d28
> 
> ... but maybe my memory also just fails and this has never been properly fixed.

In case you're using GTK, I think I just found the problem that I was 
remembering again:

https://lists.gnu.org/archive/html/qemu-ppc/2016-11/msg00142.html
https://lists.gnu.org/archive/html/qemu-ppc/2016-11/msg00143.html

I assume this has never been properly fixed.

  Thomas