Re: hdparm-9.17 released, with experimental trim/wiper scripts for SSDs

[Jeff Garzik <jeff@garzik.org>]

Robert Hancock wrote:
> Yeah, according to the datasheet "The SiI3124 will decode the 8-bit ATA
> command at PRB offset 0x0a and automatically execute the default 
> protocol for the command. In certain cases it might be desirable to 
> specify a non-default protocol to be used, such as with vendor specific 
> device commands." The DSM command seems to be DMA data-out and the chip 
> likely doesn't know that command. I have to wonder why they decided to 
> use that design instead of just making the driver indicate the protocol 
> explicitly. In any case, it looks like the driver needs code to override 
> the protocol setting for this command. (Maybe we should just set the 
> protocol override for what we know the command is supposed to be in all 
> cases?)
> 
> Sil311x will have the same problem. The solution there seems to be to 
> execute a vendor-specific command to tell the controller what protocol 
> that command code uses. Some other controllers may have similar issues 
> if they are parsing the ATA command codes.. it's possible that some of 
> them might not support DSM/TRIM commands properly.


Yes, this is a common problem for many SATA controllers, for any new 
opcode -- and for SATA<->PATA bridges too, which also snoop the opcode 
to determine certain behaviors.

	Jeff