Hi,
On Saturday 19 January 2008, Alan Cox wrote:
> The PDC202xx older devices do not support ATAPI DMA via the usual
> interfaces. What documentation I have isn't sufficient to support DMA and
> it isn't clear if the Windows drivers do this or it is possible at all.
> (Neither do the drivers/ide old drivers)
IDE pdc202xx_old host driver supports ATAPI DMA just fine and in line
with the PDC2026x programming guide.
> So turn it ATAPI DMA off, these are disk optimised controllers.
This is an acceptable workaround for 2.6.24 but it probably just hides
some deeper pata_pdc202xx_old or/and libata problem.
Thanks,
Bart
> Signed-off-by: Alan Cox <[EMAIL PROTECTED]>
>
> diff -u --new-file --recursive --exclude-from /usr/src/exclude
> linux.vanilla-2.6.24-rc8-mm1/drivers/ata/pata_pdc202xx_old.c
> linux-2.6.24-rc8-mm1/drivers/ata/pata_pdc202xx_old.c
> --- linux.vanilla-2.6.24-rc8-mm1/drivers/ata/pata_pdc202xx_old.c
> 2008-01-19 14:47:56.000000000 +0000
> +++ linux-2.6.24-rc8-mm1/drivers/ata/pata_pdc202xx_old.c 2008-01-19
> 15:19:25.000000000 +0000
> @@ -243,6 +243,24 @@
> return ata_sff_port_start(ap);
> }
>
> +/**
> + * pdc2026x_check_atapi_dma - Check whether ATAPI DMA can be supported for
> this command
> + * @qc: Metadata associated with taskfile to check
> + *
> + * Just say no - not supported on older Promise.
> + *
> + * LOCKING:
> + * None (inherited from caller).
> + *
> + * RETURNS: 0 when ATAPI DMA can be used
> + * 1 otherwise
> + */
> +
> +static int pdc2026x_check_atapi_dma(struct ata_queued_cmd *qc)
> +{
> + return 1;
> +}
> +
> static struct scsi_host_template pdc202xx_sht = {
> .module = THIS_MODULE,
> .name = DRV_NAME,
> @@ -310,6 +328,7 @@
> .post_internal_cmd = ata_bmdma_post_internal_cmd,
> .cable_detect = pdc2026x_cable_detect,
>
> + .check_atapi_dma= pdc2026x_check_atapi_dma,
> .bmdma_setup = ata_bmdma_setup,
> .bmdma_start = pdc2026x_bmdma_start,
> .bmdma_stop = pdc2026x_bmdma_stop,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
