Re: [PATCH] libata: Deal with ATA8-ACS proposed Trusted/Treacherous Computing features

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Alan Cox wrote:
Historically word 48 in the identify data was used to mean 32bit I/O was
supported for VLB IDE etc. ATA8 reassigns this word to the Trusted
Computing Group, where it is used for TCG features. This means that an
ATA8 TCG drive is going to trigger 32bit I/O on some systems which will
be funny. Perhaps thats why T13 gave them the word.

Anyway we need to sort this out ready for ATA8 so:
- Reorder the ata.h header a bit so the ata_version function occurs early
in it
- Make dword_io check the ATA version
- Add an ATA8 version checking TCG presence test

While we are at it the current drafts have a flaw where it may not be
possible to disable TCG features at boot (and opt out of the trusted
model) as TCG intends because it relies on presence of a different
optional feature (DCS). Handle this in software by refusing the TCG
commands if libata.allow_tpm is not set. (We must make it possible as
some environments such as proprietary VDR devices will doubtless want to
use it to lock up content)

Finally as with CPRM print a warning so that the user knows they may not
be able to full access and use the device.

Alan

Signed-off-by: Alan Cox <alan@xxxxxxxxxx>

would you rediff against latest torvalds/linux-2.6.git pretty please?


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