On Sat, 23 Jan 2010, Jan Kiszka wrote: > Jan Kiszka wrote: > > malc wrote: > >> On Sat, 23 Jan 2010, ondrej drbohlav wrote: > >> > >>> Hi there, > >>> > >>> I have compiled qemu 0.12.2 on an x64 ubuntu (8.10) and run MusicPal > >>> in it with SDL. > >>> MusicPal works OK but there is no sound. > >> Confirmed. > >> > >>> I have done essentially the same with qemu 0.11.1. The sound is there > >>> (thanks jki for suggesting a previous version). > >>> > >>> Please find below the configs and logs & contact me if additional info > >>> is needed. > >>> > >>> Cheers, Ondrej > >>> > >>> 1) qemu-0.12.2 > >> [..snip..] > >> > >> Someone would have to bisect it. > > > > Already done: it's b3a219883ebe21f55a8ee5e7e5b38b9eb309e9c0. But that > > patch looks sane. I guess it just revealed a hidden bug in Musicpal's > > i2c use. Need to dig deeper. > > Found, trivial patch on the way.
Will test... > > > > >> BTW, Jan, 2e87c5b937444c1155073f7b10d630e0e383e5d8 doesn't quite do > >> what i said helps[1] and conseqently musicpal enters an infinite loop > >> again... > >> > >> [1] http://lists.gnu.org/archive/html/qemu-devel/2009-09/msg00920.html > >> > > > > OK, I will have to look into the Linux driver code to check the loop > > termination conditions again. > > This still makes no sense, at least based on available driver sources > and so far observed behavior with existing firmware images: the TX queue > is always setup to form a ring, at no point the driver destroys this > ring before triggering a TX. So we are only left with a potentially > undefined (NULL) ring entry pointer, and that is what my commit tried to > catch. I rather suspect we see a subtle memory corruption here. > > Malc, when do you get this? Could you instrument the loop to check if we > get off-track before, scanning random guest memory? I asked some questions before[1] but nobody answered them.. Anyhow i'm happy to do stuff, just need to be instructed what is this stuff that needs to be done.. [1] http://lists.gnu.org/archive/html/qemu-devel/2009-10/msg00292.html -- mailto:av1...@comtv.ru
