[Qemu-devel] [PATCH 02/10] SCSI: STARTSTOPUNIT only eject/load media if powercondition is 0

[Paolo Bonzini <pbonzini@redhat.com>]

From: Ronnie Sahlberg <ronniesahlberg@gmail.com>

The START STOP UNIT command will only eject/load media if
power condition is zero.

If power condition is !0 then LOEJ and START will be ignored.

>From MMC (sbc contains similar wordings too)
  The Power Conditions field requests the block device to be placed
  in the power condition defined in
  Table 558. If this field has a value other than 0h then the Start
  and LoEj bits shall be ignored.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi-disk.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 84b63ff..e2ec177 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -1247,6 +1247,12 @@ static int scsi_disk_emulate_start_stop(SCSIDiskReq *r)
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
     bool start = req->cmd.buf[4] & 1;
     bool loej = req->cmd.buf[4] & 2; /* load on start, eject on !start */
+    int pwrcnd = req->cmd.buf[4] & 0xf0;
+
+    if (pwrcnd) {
+        /* eject/load only happens for power condition == 0 */
+        return 0;
+    }
 
     if ((s->features & (1 << SCSI_DISK_F_REMOVABLE)) && loej) {
         if (!start && !s->tray_open && s->tray_locked) {
-- 
1.7.10.4