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

[Jeff Garzik <jeff@garzik.org>]

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@redhat.com>

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