Alan Cox wrote:
> In some situations we find that SATA devices are attached via PATA/SATA
> bridges. When we find this we need to change a couple of bits of behaviour
>
> - Error changedown behaviour for SATA is different - no point
> dropping to PIO
> - 40/80 wire cable detection testing cannot be done.
>
> Thus we need to detect this case and update the cable type accordingly.
>
> Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
>
> diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.22-rc1-mm1/drivers/ata/libata-core.c linux-2.6.22-rc1-mm1/drivers/ata/libata-core.c
> --- linux.vanilla-2.6.22-rc1-mm1/drivers/ata/libata-core.c 2007-05-18 16:22:53.000000000 +0100
> +++ linux-2.6.22-rc1-mm1/drivers/ata/libata-core.c 2007-05-18 16:40:23.000000000 +0100
> @@ -2186,6 +2186,16 @@
> if (ap->ops->cable_detect)
> ap->cbl = ap->ops->cable_detect(ap);
>
> + /* We may have SATA bridge glue hiding here irrespective of the
> + reported cable types and sensed types */
> + for (i = 0; i < ATA_MAX_DEVICES; i++) {
> + dev = &ap->device[i];
> + if (!ata_dev_enabled(dev))
> + continue;
> + if (ata_id_is_sata(dev->id))
> + ap->cbl = ATA_CBL_SATA;
> + }
> +
I'm not sure this is correct. The SATA bridge can be at the far side of
PATA cable near to the drive. ie.
PATA host <========= PATA cable ==========> P/SATA bridge : SATA drive
In this case, most of the cable is PATA and cable detection matters.
Another problem is that there are still codes which interpret ap->cbl ==
ATA_CBL_SATA as SATA host port. They need to be fixed first before
using ap->cbl for the actual cable type.
--
tejun
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