Jeff Garzik wrote: > Brian King wrote: >> Jeff Garzik wrote: >>> James Bottomley wrote: >>>> This really doesn't look correct. What you want is a sata transport >>>> class with a max command length in the host device. >>> Christoph Hellwig wrote: >>>> this sounds wrong to me. cdb length is a limitation of the host (driver). >>>> A target will reject unknown commands, no matter what length they have. >>> In practice, CDB length may be limited by both the host and the device. >>> This applies to ATAPI, and some USB storage too IIRC. For ATAPI, you >>> read the CDB length from the device's IDENTIFY PACKET DEVICE info page. >> So the question remains, do we need to police the CDB length on a per device >> basis, or is a per host basis ok? Will we have ATAPI devices falling on the >> floor if they get sent too large of a cdb? > > It _must_ be limited by both device and host. If you have a device that > supports 16-byte CDBs and a host controller which only supports 12-byte > CDBs, clearly the limit is 12, due to host. However, a reversed > situation (limited by device) is equally plausible/possible. Ok. That is what I was assuming, which was the reason I submitted this patch in the first place. James, given this information, are you ok with the patch, or do you still have an objection? Thanks, Brian -- Brian King eServer Storage I/O IBM Linux Technology Center - : send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
