On Fri, 2 Apr 2010, Alan Stern wrote: > > Best guess (and it's a guess only) would be that the USB bridge SAT > > layer doesn't implement ATA_16 and so fails in interesting ways when it > > comes in. Does the ATA_12 version of IDENTIFY DEVICE succeed? > > It does. And in between the two is an ATA_16 SET FEATURES command > which also (apparently) succeeds. That is, there is no error > indication from the device -- but goodness knows if it actually carries > out the command. Incidentally, there's a discussion of this problem with input from an engineer at the company that makes the bridge chip here: https://bugs.launchpad.net/ubuntu/+source/linux-fsl-imx51/+bug/431963 See comment #25 and later. He claims that the ATA pass-through command contains a SECTOR COUNT field of 0 even though it asks for 512 bytes of IDENTIFY data. This invalid parameter combination causes the bridge chip to get confused, and instead of failing gracefully, it messes up the USB protocol. Does anybody know where to find out why hdparm is sending an IDENTIFY command with invalid parameters? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
