[SCSI] sr: update to follow tray status correctly

Based on an original patch from: David Martin <tasio@tasio.net>

When trying to get the drive status via ioctl CDROM_DRIVE_STATUS, with
no disk it gives CDS_TRAY_OPEN even if the tray is closed.

ioctl works as expected with ide-cd driver.

Gentoo bug report: http://bugs.gentoo.org/show_bug.cgi?id=196879

Cc: Maarten Bressers <mbres@gentoo.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sr.c

@@ -67,8 +67,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
 
 #define SR_DISKS	256
 
-#define MAX_RETRIES	3
-#define SR_TIMEOUT	(30 * HZ)
 #define SR_CAPABILITIES \
 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \

drivers/scsi/sr.h

@@ -20,6 +20,9 @@
 #include <linux/genhd.h>
 #include <linux/kref.h>
 
+#define MAX_RETRIES	3
+#define SR_TIMEOUT	(30 * HZ)
+
 struct scsi_device;
 
 /* The CDROM is fairly slow, so we need a little extra time */

drivers/scsi/sr_ioctl.c

@@ -275,18 +275,6 @@ int sr_do_ioctl(Scsi_CD *cd, struct packet_command *cgc)
 /* ---------------------------------------------------------------------- */
 /* interface to cdrom.c                                                   */
 
-static int test_unit_ready(Scsi_CD *cd)
-{
-	struct packet_command cgc;
-
-	memset(&cgc, 0, sizeof(struct packet_command));
-	cgc.cmd[0] = GPCMD_TEST_UNIT_READY;
-	cgc.quiet = 1;
-	cgc.data_direction = DMA_NONE;
-	cgc.timeout = IOCTL_TIMEOUT;
-	return sr_do_ioctl(cd, &cgc);
-}
-
 int sr_tray_move(struct cdrom_device_info *cdi, int pos)
 {
 	Scsi_CD *cd = cdi->handle;
@@ -310,14 +298,46 @@ int sr_lock_door(struct cdrom_device_info *cdi, int lock)
 
 int sr_drive_status(struct cdrom_device_info *cdi, int slot)
 {
+	struct scsi_cd *cd = cdi->handle;
+	struct scsi_sense_hdr sshdr;
+	struct media_event_desc med;
+
 	if (CDSL_CURRENT != slot) {
 		/* we have no changer support */
 		return -EINVAL;
 	}
-	if (0 == test_unit_ready(cdi->handle))
+	if (0 == scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES,
+				      &sshdr))
 		return CDS_DISC_OK;
 
-	return CDS_TRAY_OPEN;
+	if (!cdrom_get_media_event(cdi, &med)) {
+		if (med.media_present)
+			return CDS_DISC_OK;
+		else if (med.door_open)
+			return CDS_TRAY_OPEN;
+		else
+			return CDS_NO_DISC;
+	}
+
+	/*
+	 * 0x04 is format in progress .. but there must be a disc present!
+	 */
+	if (sshdr.sense_key == NOT_READY && sshdr.asc == 0x04)
+		return CDS_DISC_OK;
+
+	/*
+	 * If not using Mt Fuji extended media tray reports,
+	 * just return TRAY_OPEN since ATAPI doesn't provide
+	 * any other way to detect this...
+	 */
+	if (scsi_sense_valid(&sshdr) &&
+	    /* 0x3a is medium not present */
+	    sshdr.asc == 0x3a)
+		return CDS_NO_DISC;
+	else
+		return CDS_TRAY_OPEN;
+
+	return CDS_DRIVE_NOT_READY;
 }
 
 int sr_disk_status(struct cdrom_device_info *cdi)