>Is there any way for the lp driver to tell the parport driver whether
>or not to use DMA? I'm pretty sure this is not a long-term solution
>to the problem but I'd like to try it.
Don't think so. If you just want a quick hack, you can try removing the
assignment to p->ops->compat_write_data in this code from parport_pc:
#ifdef CONFIG_PARPORT_PC_FIFO
if (p->dma != PARPORT_DMA_NOFIFO &&
priv->fifo_depth > 0 && p->irq != PARPORT_IRQ_NONE) {
p->ops->compat_write_data = parport_pc_compat_write_block_pio;
#ifdef CONFIG_PARPORT_1284
p->ops->ecp_write_data = parport_pc_ecp_write_block_pio;
/* currently broken, but working on it.. (FB) */
/* p->ops->ecp_read_data = parport_pc_ecp_read_block_pio; */
#endif /* IEEE 1284 support */
[...]
>Beyond that, has anyone seen any similar problems? Any ideas for things
>to try?
I haven't heard of similar problems, but I suspect the DMA-assisted
compatibility mode stuff hasn't seen all that much testing.
What kind of failure are you seeing -- is it just the same sort of
non-specific corruption you were getting in the software ECP case?
p.
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This archive was generated by hypermail 2b29 : Wed Aug 29 2001 - 16:48:06 EDT