Re: [PATCH] libata: fix ATA passthrough handling for ATAPI devices

[Jeff Garzik <jgarzik@pobox.com>]

Douglas Gilbert wrote:
> The 16 byte CDB that Tejun is talking about is the
> ATA PASS THROUGH (16) SCSI command. That is valid to

I'm talking about the changes to the implementation, which appear to 
mistakenly allow 16-byte CDBs through to the ATAPI device, even if it 
only supports 12-byte CDBs.

I am quite aware of the ATA passthru SCSI command.  Heck, the spec had 
input from me.  I'm talking about something different.


> The only clash between MMC and SATL SCSI opcodes is
> with opcode 0xA1: BLANK in MMC and ATA PASS THROUGH (12)

Ok, so the answer is, yes there is a clash, and thus this change will 
remove the ability for working-today setups to use BLANK.

In order to avoid breaking working setups, a method must be found which 
tells the SATL to not filter out the ATA passthru commands.


> This is all about being able to send ATA commands to
> ATAPI devices that are valid for PACKET devices, examples:
>     IDENTIFY PACKET DEVICE
>     SET FEATURES
>     IDENTIFY DEVICE (should abort command + set signature)
>     DEVICE RESET
> and I assume there are others.

I am quite aware of the purpose of ATA passthru :)

	Jeff