> > I also have encountered problems with the MediaGX and the OSS/Free
> > sound drivers. The ALSA drivers seem to work well with the GXm but
> > I have had problems with sound within a JVM. I wondered what your
> > suggested work around to the problem is ?
>
> Are you talking about the soundblaster emulation in the
> BIOS using VSA? We have worked very closely with National
> Semiconductor (for some Geode-related projects) and have
> figured out that 8-bit sound will not work correctly with
> the current OSS/Free sb driver (which probably is what
> your JVM trying to use). The patch is very simple:
>
> Look for the part on DMA buffer where it is defined as
> 64K, change it 32K (or any size less than 64K) and your
> sb driver will now work for both 16-bit and 8-bit
> emulation.
>
> This is due to some mistakes in VSA code and hopefully
> NS will release some updated code for BIOS updates.
Thanks Eric / T.J. - Yes it is the soundblaster emulation in the BIOS.
Standard settings of 0x220, 5, 1, 5 except that the MPU401 is disabled
as the Linux box seems to lock up with it enabled.
The CPU is the MediaGX-233 with 5530 companion. I'm not sure about the
VSA code version but I think it is the latest worker that was available
from Cyrix back before NS took over.
I am including sound support as modules (soundcore, soundlow, sound,
uart401, sb)
The MPU401 I/O base is not specified to the command line of sb.o and the
source
seems to show that it defaults to disabled.
I did the mod. to 'sound_config.h' as you suggested and changed the
DSP_BUFFSIZE
from 64Kb to 32Kb (also tried 16Kb). Recompiled the modules (Kernel
2.2.12-20) and
updated my LinuxBox with sb.o, sound.o, uart401.o.
I checked that the DMA buffer sizes had actually changed with some printk()
messaging.
Unfortuately XMMS under GNOME (for example) is still playing .WAV files with
lots of
buzzing/clicking.
I wondered if there are any obvious mistakes in the above - or if you had
any other thoughts ?
Thanks again,
Alex
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