[MPlayer-dev-eng] mplayer cdda triggers sg_write log storm in kernel

[Tobias Jakobi]

Hello mplayer people,

I have a problem with my current system. I just updated kernel and
switched to the new ATA layer. To get CDDA support for mplayer back I
also had to load the sg kernel module. Letting mplayer extract from
/dev/sg devices works, but produces a lot of sg_write log mesages in the
kernel log. As long as mplayer is playing messages of this type appear:

sg_write: data in/out 30576/30576 bytes for SCSI command 0xbe--guessing
data in;
   program mplayer not setting count and/or reply_len properly

metalog already suppresses a lot of these, but that doesn't solve the
problem. It seems the problem is not new:
http://readlist.com/lists/vger.kernel.org/linux-kernel/25/125901.html

I'm not completly sure but I think mplayer uses cdparanoia for
extraction, right?

The mailing list entry suggests to remove the log commands from the sg.c
sourcefile, but I'm hoping for a more complete fix of the problem. I
already posted this problem to the Gentoo forums (I'm using Gentoo
linux) and also intend to make the cdparanoia people aware that the
problem still exists.

Does anyone know of a (non-hacky) patch to solve this?

uname -a:
Linux voodoomaster 2.6.21-gentoo-r3 #1 Sat Jul 7 20:10:22 CEST 2007
x86_64 AMD Athlon(tm) 64 Processor 3500+ AuthenticAMD GNU/Linux
(it also appear on two more systems, so I don't think it's 64bit related)

mplayer is built from ebuild mplayer-1.0.20070622-r1 (I suppose it's a
SVN copy)
I report this upstream because it has nothing to do with the
distribution I use, and I can even reproduce it when building directly
from source.

Thanks,
Tobias Jakobi