[ltp] T43: No DMA for /dev/hdc (Ultrabay Slim HDD)

[Henrique de Moraes Holschuh]

On Fri, 08 Dec 2006, Daniel Skorka wrote:
> It was partially clear to me. I knew that there was a SATA-PATA bridge
> for the system drive. I wasn't sure whether this extended to all IDE

On the T43 and R52.  The *60 advanced ultrabay is probably 100% SATA.  I
would actually like to know for sure about this.  Anyone with a *60 can
comment on it?  Can you plug a PATA device to the T60/X60/Z60/Z61 advanced
ultrabay?  Does it require a device caddy with microchips on it (which?) ?

> devices. I also thought that using a PATA disk on this bridge required
> a special firmware inside the disk.

HDAPS require special firmware on many disks, PATA or SATA.  It is also
heavly suspected that the SATA-PATA bridge causes trouble for non-ATAPI DMA
transfers and also need some sort of disk firmware fixup, but this is not
100% certain.

That said, I am reconsidering what I wrote. I am 100% sure the channel to
the *internal* HD bay is SATA, and that one does have a SATA-PATA bridge.
But thinking a bit more about it, I got some doubts whether the secondary
channel to the bay is SATA or PATA (you *still* need libata to talk to it
with DMA anyway, because of the Linux ICH support).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh