Re: DMA memory shortage
On Thu, 29 Apr 1999, John Leget wrote:
> Running 2.2.6-ac2, potato , ASUS P2B-DS Dual 450, 128Mb, SCSI Disks ,IDE
> CDROM (hda ),ZIP (hdc)
>
> In my continuing crusade to get info from my CDROM for mp3's :), ive
> just come across the following
>
> Apr 28 21:33:22 gabriel kernel: DMA memory shortage. Temporarily falling
> back on virtual DMA
>
> This popped up after i recompiled the kernel and ran lilo
>
> Apr 28 22:15:49 gabriel kernel: floppy0: unexpected interrupt
> Apr 28 22:15:49 gabriel kernel: floppy0: sensei repl[0]=80
ISA DMA (which the floppy and sound card in particular use) is only
available for the lower 16MB of memory. This dates back to when the first
8088 PC's were built. If you use up the memory below 16MB for whatever
reason, and the kernel isn't holding onto some DMA space, you can be out
of luck.
The simple way to fix this is to compile the sound and floppy drivers
into the kernel, not as modules. The drivers grab their DMA memory on boot
and hold onto it forever. Since you have 128MB I don't think you'll miss
the ~128K this involves.
If you really want or need to do it as modules (e.g., ISA PNP sound card)
I think there are options to lock the buffers in place, but I don't know
what they are.
Sincerely,
Ray Ingles (248) 377-7735 ray.ingles@fanucrobotics.com
"Monkeys would be harder on equipment than college students,
but only because they're stronger." - Jim Ingles
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