Re: [PARPORT] Parallel port DMA channel usage

Grant R. Guenther (
Sun, 29 Mar 1998 08:41:28 -0500 (EST)

> I've just started using an external SparQ drive with paride, and everything
> works great. But the performance isn't that great, and the machine grinds to a
> halt whenever I transfer large amounts of data to/from the disk.

Please include the kernel log messages that are reported when you load the
PARIDE modules, and give us some indication of what sort of performance you
are seeing. With a properly tuned PARIDE installation, you should be able
to achieve close to 500KB/s transfer rates.

> From what I saw, paride makes no use of the parallel port DMA channel. Is
> there any way for it to do so ? My machine is a P5-133MMX, Linux 2.0.33, paride
> 0.94.

The DMA channel is only used in ECP modes. PARIDE does not support ECP.
If you have your parallel port configured into an ECP mode, you will probably
get SPP performance. Check the "mode" reported when you load pd. You want
to be in mode 5. Also, you should probably force the "delay" parameter
to 0 when you load pd.

Grant R. Guenther

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