[Qemu-devel] Re: [PATCH] char: Flush read buffer in mux_chr_can_read

[Alexander Graf]

On 15.05.2010, at 10:36, Jan Kiszka wrote:

> Alexander Graf wrote:
>> On 14.05.2010, at 18:17, Jan Kiszka wrote:
>>> Alexander Graf wrote:
>>>> Now that I can finally reproduce the bug with --enable-io-thread, I can 
>>>> verify that it does *not* fix the issue.
>>> I do not trust your tests. :p
>>> 
>>> I just tried to reproduce with --enable-io-thread and the setup I
>>> described above - all still fine here. Can you reproduce with an x86 guest?
>> 
>> Nope, it works fine with an x86 guest. I put the following in /etc/inittab 
>> of my guest:
>> 
>> 11:2345:respawn:/sbin/mingetty --noclear /dev/hvc0 linux
>> 
>> One major thing to keep in mind when talking about s390 guests is that we 
>> almost never trap into userspace.
> 
> Do you have the same problem when using an unbuffered backend, e.g. pty?
> Maybe that single-byte "fifo" of stdio makes the difference, though I
> wonder why only on s390 (guest exists should not block the polling done
> by the io-thread, just accelerate it).

Mind to give me a small example on how to use that? :)

Alex