On (Thu) 07 Apr 2011 [10:59:20], Kevin Wolf wrote:
> Am 07.04.2011 07:05, schrieb Amit Shah:
> > We restrict the commands that a guest can send us after a cdrom change
> > event. The current list includes REQUEST_SENSE and INQUIRY commands.
> > Guests can also issue TEST_UNIT_READY to inquire for the status, so
> > allow this command as well.
> >
> > Signed-off-by: Amit Shah <amit.s...@redhat.com>
>
> Hm... MMC-5, section 4.1.6.1 seems to conflict with this:
>
> "If a Host issues a command other than GET CONFIGURATION, GET EVENT
> STATUS NOTIFICATION, INQUIRY or REQUEST SENSE while a unit attention
> condition exists for that Host, the Drive shall not perform the command
> and shall report CHECK CONDITION status unless a higher priority status
> as defined by the Drive is also pending."
>
> So while you're right that our list is incomplete, TEST UNIT READY
> doesn't seem to be among the missing commands.
Hm - older Linux guests (pre 2.6.38) and Windows guests, as Gleb's
commit mentioned, rely on this command to get CD change notifications:
/* identical to scsi_test_unit_ready except that it doesn't
* eat the NOT_READY returns for removable media */
int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
{
int retries = MAX_RETRIES;
int the_result;
u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
* conditions are gone, or a timeout happens
*/
do {
the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
0, sshdr, SR_TIMEOUT,
retries--, NULL);
if (scsi_sense_valid(sshdr) &&
sshdr->sense_key == UNIT_ATTENTION)
sdev->changed = 1;
} while (retries > 0 &&
(!scsi_status_is_good(the_result) ||
(scsi_sense_valid(sshdr) &&
sshdr->sense_key == UNIT_ATTENTION)));
return the_result;
}
There could be something else brewing as well. We never report a
'tray open' condition; maybe the guest will be happy with such a thing
as well. Will have to check.
Amit
