Tejun Heo wrote:
libata used to pass all SCSI commands directly to ATAPI devices.
However, this is incorrect for ATA passthrough commands as they must
be handled by the SAT layer in libata. Also, regardless of the
attached ATAPI device's supported packet length, SAT says that both
flavors of passthrough commands (ATA12 and ATA16) should work.
This patch makes the following changes to fix ATA passthrough handling
for ATAPI devices.
* implement atapi_get_xlat_func() and make libata handle ATA12 and
ATA16 in SAT layer instead of passing it directly to the target
device even if the device is ATAPI.
* Always allow 16byte CDBs for ATAPI devices. This makes
This is definitely wrong. Some ATAPI devices are limited to 12-byte CDBs.
Also, are we sure that no ATAPI device ever implements these opcodes?
Prior to the SAT spec -- which includes most ATAPI firmwares -- those
opcodes might have been vendor-reserved space. Did you or Doug verify
against the older specifications who might care about these opcodes?
Or maybe there is a flag somewhere we can abuse, that permits support of
both scenarios -- passing the command to the device, and handling the
command internally?
Jeff
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