On Wed, Apr 8, 2009 at 11:33 PM, Mark Lord <liml@xxxxxx> wrote: > > Matthew Wilcox wrote: >> >> From: David Woodhouse <David.Woodhouse@xxxxxxxxx> >> >> Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx> >> [modified to reduce amount of special casing needed for discard] >> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> >> --- > > .. >> >> + task->tf.command = ATA_CMD_DSM; >> + task->tf.feature = ATA_DSM_TRIM; >> + task->tf.hob_feature = 0x00; >> + task->tf.nsect = size / 512; >> + task->tf.hob_nsect = (size / 512) >> 8; > > .. > > Matthew (or others), > > Could you perhaps explain what the purpose of the data portion > of this command is for? The draft ATA spec I have here has mangled > text in the description -- like it's missing a crucial sentence there. > > So it's not obvious exactly why this command even needs data to > be transfered. It's for transfering list of LBA ranges which composed of LBA offset (48bit) and length of data to be trimmed (16bit). -- Dongjun -- To unsubscribe from this list: 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
