Merge raven.il.steeleye.com:/home/jejb/BK/scsi-misc-2.5

into raven.il.steeleye.com:/home/jejb/BK/scsi-for-linus-2.5

drivers/block/scsi_ioctl.c

@@ -40,6 +40,11 @@ const unsigned char scsi_command_size[8] =
 
 #define BLK_DEFAULT_TIMEOUT	(60 * HZ)
 
+/* defined in ../scsi/scsi.h  ... should it be included? */
+#ifndef SCSI_SENSE_BUFFERSIZE
+#define SCSI_SENSE_BUFFERSIZE 64
+#endif
+
 int blk_do_rq(request_queue_t *q, struct block_device *bdev, struct request *rq)
 {
 	DECLARE_COMPLETION(wait);
@@ -126,11 +131,11 @@ static int sg_io(request_queue_t *q, struct block_device *bdev,
 		 struct sg_io_hdr *uptr)
 {
 	unsigned long uaddr, start_time;
-	int err, reading, writing, nr_sectors;
+	int reading, writing, nr_sectors;
 	struct sg_io_hdr hdr;
 	struct request *rq;
 	struct bio *bio;
-	char sense[24];
+	char sense[SCSI_SENSE_BUFFERSIZE];
 	void *buffer;
 
 	if (!access_ok(VERIFY_WRITE, uptr, sizeof(*uptr)))
@@ -265,26 +270,36 @@ static int sg_io(request_queue_t *q, struct block_device *bdev,
 
 	start_time = jiffies;
 
-	/*
-	 * return -EIO if we didn't transfer all data, caller can look at
-	 * residual count to find out how much did succeed
+	/* ignore return value. All information is passed back to caller
+	 * (if he doesn't check that is his problem).
+	 * N.B. a non-zero SCSI status is _not_ necessarily an error.
 	 */
-	err = blk_do_rq(q, bdev, rq);
-	if (rq->data_len > 0)
-		err = -EIO;
+	blk_do_rq(q, bdev, rq);
 	
 	if (bio) {
 		bio_unmap_user(bio, reading);
 		bio_put(bio);
 	}
 
-	hdr.status = rq->errors;
+	/* write to all output members */
+	hdr.status = rq->errors;	
+	hdr.masked_status = (hdr.status >> 1) & 0x1f;
+	hdr.msg_status = 0;
+	hdr.host_status = 0;
+	hdr.driver_status = 0;
+	hdr.info = 0;
+	if (hdr.masked_status || hdr.host_status || hdr.driver_status)
+		hdr.info |= SG_INFO_CHECK;
 	hdr.resid = rq->data_len;
 	hdr.duration = (jiffies - start_time) * (1000 / HZ);
+	hdr.sb_len_wr = 0;
 
 	if (rq->sense_len && hdr.sbp) {
-		if (!copy_to_user(hdr.sbp,rq->sense, rq->sense_len))
-			hdr.sb_len_wr = rq->sense_len;
+		int len = (hdr.mx_sb_len < rq->sense_len) ? 
+				hdr.mx_sb_len : rq->sense_len;
+
+		if (!copy_to_user(hdr.sbp, rq->sense, len))
+			hdr.sb_len_wr = len;
 	}
 
 	blk_put_request(rq);
@@ -297,8 +312,9 @@ static int sg_io(request_queue_t *q, struct block_device *bdev,
 
 		kfree(buffer);
 	}
-
-	return err;
+	/* may not have succeeded, but output values written to control
+	 * structure (struct sg_io_hdr).  */
+	return 0;
 }
 
 #define FORMAT_UNIT_TIMEOUT		(2 * 60 * 60 * HZ)

drivers/scsi/hosts.c

@@ -36,6 +36,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
+#include <linux/completion.h>
 
 #define __KERNEL_SYSCALLS__
 
@@ -314,9 +315,10 @@ int __scsi_add_host(struct Scsi_Host *shost)
  **/
 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 {
-	dev->class_data = shost;
-	shost->host_gendev = dev;
-
+	if (dev) {
+		dev->class_data = shost;
+		shost->host_gendev = dev;
+	}
 	return __scsi_add_host(shost);
 }
 
@@ -335,10 +337,11 @@ void scsi_unregister(struct Scsi_Host *shost)
 	 * Next, kill the kernel error recovery thread for this host.
 	 */
 	if (shost->ehandler) {
-		DECLARE_MUTEX_LOCKED(sem);
+		DECLARE_COMPLETION(sem);
 		shost->eh_notify = &sem;
-		send_sig(SIGHUP, shost->ehandler, 1);
-		down(&sem);
+		shost->eh_kill = 1;
+		up(shost->eh_wait);
+		wait_for_completion(&sem);
 		shost->eh_notify = NULL;
 	}
 
@@ -368,7 +371,7 @@ struct Scsi_Host * scsi_register(Scsi_Host_Template *shost_tp, int xtr_bytes)
 {
 	struct Scsi_Host *shost, *shost_scr;
 	int gfp_mask;
-	DECLARE_MUTEX_LOCKED(sem);
+	DECLARE_COMPLETION(sem);
 
         /* Check to see if this host has any error handling facilities */
         if(shost_tp->eh_strategy_handler == NULL &&
@@ -464,7 +467,7 @@ struct Scsi_Host * scsi_register(Scsi_Host_Template *shost_tp, int xtr_bytes)
 	 * Now wait for the kernel error thread to initialize itself
 	 * as it might be needed when we scan the bus.
 	 */
-	down(&sem);
+	wait_for_completion(&sem);
 	shost->eh_notify = NULL;
 
 	shost->hostt->present++;

drivers/scsi/hosts.h

@@ -381,11 +381,12 @@ struct Scsi_Host
     struct task_struct    * ehandler;  /* Error recovery thread. */
     struct semaphore      * eh_wait;   /* The error recovery thread waits on
                                           this. */
-    struct semaphore      * eh_notify; /* wait for eh to begin */
+    struct completion     * eh_notify; /* wait for eh to begin or end */
     struct semaphore      * eh_action; /* Wait for specific actions on the
                                           host. */
     unsigned int            eh_active:1; /* Indicates the eh thread is awake and active if
                                           this is true. */
+    unsigned int            eh_kill:1; /* set when killing the eh thread */
     wait_queue_head_t       host_wait;
     Scsi_Host_Template    * hostt;
     atomic_t                host_active; /* commands checked out */

drivers/scsi/scsi_error.c

@@ -27,6 +27,7 @@
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/smp_lock.h>
+#include <linux/completion.h>
 
 #define __KERNEL_SYSCALLS__
 
@@ -41,20 +42,6 @@
 
 #include <scsi/scsi_ioctl.h> /* grr */
 
-/*
- * We must always allow SHUTDOWN_SIGS.  Even if we are not a module,
- * the host drivers that we are using may be loaded as modules, and
- * when we unload these,  we need to ensure that the error handler thread
- * can be shut down.
- *
- * Note - when we unload a module, we send a SIGHUP.  We mustn't
- * enable SIGTERM, as this is how the init shuts things down when you
- * go to single-user mode.  For that matter, init also sends SIGKILL,
- * so we mustn't enable that one either.  We use SIGHUP instead.  Other
- * options would be SIGPWR, I suppose.
- */
-#define SHUTDOWN_SIGS	(sigmask(SIGHUP))
-
 #ifdef DEBUG
 #define SENSE_TIMEOUT SCSI_TIMEOUT
 #else
@@ -1589,12 +1576,10 @@ void scsi_error_handler(void *data)
 	int rtn;
 	DECLARE_MUTEX_LOCKED(sem);
 
-	/*
-	 * We only listen to signals if the HA was loaded as a module.
-	 * If the HA was compiled into the kernel, then we don't listen
-	 * to any signals.
-	 */
-	siginitsetinv(&current->blocked, SHUTDOWN_SIGS);
+	spin_lock_irq(&current->sig->siglock);
+	sigfillset(&current->blocked);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sig->siglock);
 
 	lock_kernel();
 
@@ -1618,9 +1603,9 @@ void scsi_error_handler(void *data)
 	/*
 	 * Wake up the thread that created us.
 	 */
-	SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent \n"));
+	SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of scsi_eh_%d\n",shost->host_no));
 
-	up(shost->eh_notify);
+	complete(shost->eh_notify);
 
 	while (1) {
 		/*
@@ -1628,7 +1613,7 @@ void scsi_error_handler(void *data)
 		 * away and die.  This typically happens if the user is
 		 * trying to unload a module.
 		 */
-		SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler sleeping\n"));
+		SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d sleeping\n",shost->host_no));
 
 		/*
 		 * Note - we always use down_interruptible with the semaphore
@@ -1640,10 +1625,10 @@ void scsi_error_handler(void *data)
 		 * semaphores isn't unreasonable.
 		 */
 		down_interruptible(&sem);
-		if (signal_pending(current))
+		if (shost->eh_kill)
 			break;
 
-		SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler waking up\n"));
+		SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d waking up\n",shost->host_no));
 
 		shost->eh_active = 1;
 
@@ -1671,7 +1656,7 @@ void scsi_error_handler(void *data)
 
 	}
 
-	SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler exiting\n"));
+	SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d exiting\n",shost->host_no));
 
 	/*
 	 * Make sure that nobody tries to wake us up again.
@@ -1691,13 +1676,9 @@ void scsi_error_handler(void *data)
 	/*
 	 * If anyone is waiting for us to exit (i.e. someone trying to unload
 	 * a driver), then wake up that process to let them know we are on
-	 * the way out the door.  This may be overkill - I *think* that we
-	 * could probably just unload the driver and send the signal, and when
-	 * the error handling thread wakes up that it would just exit without
-	 * needing to touch any memory associated with the driver itself.
+	 * the way out the door.
 	 */
-	if (shost->eh_notify != NULL)
-		up(shost->eh_notify);
+	complete_and_exit(shost->eh_notify, 0);
 }
 
 /**

drivers/scsi/scsi_lib.c

@@ -495,6 +495,7 @@ void scsi_io_completion(Scsi_Cmnd * SCpnt, int good_sectors,
 	int this_count = SCpnt->bufflen >> 9;
 	request_queue_t *q = SCpnt->device->request_queue;
 	struct request *req = SCpnt->request;
+	int clear_errors = 1;
 
 	/*
 	 * We must do one of several things here:
@@ -528,10 +529,22 @@ void scsi_io_completion(Scsi_Cmnd * SCpnt, int good_sectors,
 		kfree(SCpnt->buffer);
 	}
 
-	if (blk_pc_request(req)) {
-		req->errors = result & 0xff;
-		if (!result)
+	if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
+		req->errors = (driver_byte(result) & DRIVER_SENSE) ?
+			      (CHECK_CONDITION << 1) : (result & 0xff);
+		if (!result) 
 			req->data_len -= SCpnt->bufflen;
+		else {
+			clear_errors = 0;
+			if (SCpnt->sense_buffer[0] & 0x70) {
+				int len = 8 + SCpnt->sense_buffer[7];
+
+				if (len > SCSI_SENSE_BUFFERSIZE)
+					len = SCSI_SENSE_BUFFERSIZE;
+				memcpy(req->sense, SCpnt->sense_buffer,  len);
+				req->sense_len = len;
+			}
+		}
 	}
 
 	/*
@@ -552,7 +565,8 @@ void scsi_io_completion(Scsi_Cmnd * SCpnt, int good_sectors,
 					      req->nr_sectors, good_sectors));
 		SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n ", SCpnt->use_sg));
 
-		req->errors = 0;
+		if (clear_errors)
+			req->errors = 0;
 		/*
 		 * If multiple sectors are requested in one buffer, then
 		 * they will have been finished off by the first command.

drivers/scsi/scsi_sysfs.c

@@ -213,6 +213,7 @@ sdev_rd_attr (device_blocked, "%d\n");
 sdev_rd_attr (current_queue_depth, "%d\n");
 sdev_rd_attr (new_queue_depth, "%d\n");
 sdev_rd_attr (type, "%d\n");
+sdev_rd_attr (scsi_level, "%d\n");
 sdev_rd_attr (access_count, "%d\n");
 sdev_rd_attr (vendor, "%.8s\n");
 sdev_rd_attr (model, "%.16s\n");
@@ -224,6 +225,7 @@ static struct device_attribute * const sdev_attrs[] = {
 	&dev_attr_current_queue_depth,
 	&dev_attr_new_queue_depth,
 	&dev_attr_type,
+	&dev_attr_scsi_level,
 	&dev_attr_access_count,
 	&dev_attr_vendor,
 	&dev_attr_model,

drivers/scsi/sd.c

@@ -79,7 +79,7 @@ struct scsi_disk {
 	u8		media_present;
 	u8		write_prot;
 	unsigned	WCE : 1;	/* state of disk WCE bit */
-	unsigned	RCD : 1;	/* state of disk RCD bit */
+	unsigned	RCD : 1;	/* state of disk RCD bit, unused */
 };
 
 static LIST_HEAD(sd_devlist);
@@ -217,7 +217,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	block = SCpnt->request->sector;
 	this_count = SCpnt->request_bufflen >> 9;
 
-	SCSI_LOG_HLQUEUE(1, printk("sd_command_init: disk=%s, block=%llu, "
+	SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
 			    "count=%d\n", disk->disk_name, (unsigned long long)block, this_count));
 
 	if (!sdp || !sdp->online ||
@@ -809,9 +809,22 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
 		if (media_not_present(sdkp, SRpnt))
 			return;
 
-		/* Look for devices that return NOT_READY.
-		 * Issue command to spin up drive for these cases. */
-		if (the_result && SRpnt->sr_sense_buffer[2] == NOT_READY) {
+		if (the_result == 0)
+			break;		/* all is well now */
+
+		/*
+		 * If manual intervention is required, or this is an
+		 * absent USB storage device, a spinup is meaningless.
+		 */
+		if (SRpnt->sr_sense_buffer[2] == NOT_READY &&
+		    SRpnt->sr_sense_buffer[12] == 4 /* not ready */ &&
+		    SRpnt->sr_sense_buffer[13] == 3)
+			break;		/* manual intervention required */
+
+		/*
+		 * Issue command to spin up drive when not ready
+		 */
+		if (SRpnt->sr_sense_buffer[2] == NOT_READY) {
 			unsigned long time1;
 			if (!spintime) {
 				printk(KERN_NOTICE "%s: Spinning up disk...",
@@ -839,7 +852,7 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
 			} while(time1);
 			printk(".");
 		}
-	} while (the_result && spintime &&
+	} while (spintime &&
 		 time_after(spintime_value + 100 * HZ, jiffies));
 
 	if (spintime) {
@@ -850,80 +863,6 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
 	}
 }
 
-/*
- * sd_read_cache_type - called only from sd_init_onedisk()
- */
-static void
-sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
-		   struct scsi_request *SRpnt, unsigned char *buffer) {
-
-	unsigned char cmd[10];
-	int the_result, retries;
-
-	retries = 3;
-	do {
-
-		memset((void *) &cmd[0], 0, 10);
-		cmd[0] = MODE_SENSE;
-		cmd[1] = 0x08;	/* DBD */
-		cmd[2] = 0x08;	/* current values, cache page */
-		cmd[4] = 128;	/* allocation length */
-
-
-		memset((void *) buffer, 0, 24);
-		SRpnt->sr_cmd_len = 0;
-		SRpnt->sr_sense_buffer[0] = 0;
-		SRpnt->sr_sense_buffer[2] = 0;
-
-		SRpnt->sr_data_direction = SCSI_DATA_READ;
-		scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
-			    128, SD_TIMEOUT, SD_MAX_RETRIES);
-
-		the_result = SRpnt->sr_result;
-		retries--;
-
-	} while (the_result && retries);
-
-	if (the_result) {
-		if(status_byte(the_result) == CHECK_CONDITION
-		   && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
-		   && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
-		   /* The next are ASC 0x24 ASCQ 0x00: Invalid field in CDB */
-		   && SRpnt->sr_sense_buffer[12] == 0x24
-		   && SRpnt->sr_sense_buffer[13] == 0x00) {
-			printk(KERN_NOTICE "SCSI device %s: cache data unavailable\n", diskname);
-		} else {
-			printk(KERN_ERR "%s : MODE SENSE failed.\n"
-			       "%s : status = %x, message = %02x, host = %d, driver = %02x \n",
-			       diskname, diskname,
-			       status_byte(the_result),
-			       msg_byte(the_result),
-			       host_byte(the_result),
-			       driver_byte(the_result)
-			       );
-			if (driver_byte(the_result) & DRIVER_SENSE)
-				print_req_sense("sd", SRpnt);
-			else
-				printk(KERN_ERR "%s : sense not available. \n", diskname);
-			
-			printk(KERN_ERR "%s : assuming drive cache: write through\n", diskname);
-		}
-		sdkp->WCE = 0;
-		sdkp->RCD = 0;
-	} else {
-		const char *types[] = { "write through", "none", "write back", "write back, no read (daft)" };
-		int ct = 0;
-		int offset = buffer[3] + 4; /* offset to start of mode page */
-
-		sdkp->WCE = (buffer[offset + 2] & 0x04) == 0x04;
-		sdkp->RCD = (buffer[offset + 2] & 0x01) == 0x01;
-
-		ct =  sdkp->RCD + 2*sdkp->WCE;
-
-		printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n", diskname, types[ct]);
-	}
-}
-
 /*
  * read disk capacity - called only in sd_init_onedisk()
  */
@@ -1102,11 +1041,12 @@ sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 
 static int
 sd_do_mode_sense6(struct scsi_device *sdp, struct scsi_request *SRpnt,
-		  int modepage, unsigned char *buffer, int len) {
+		  int dbd, int modepage, unsigned char *buffer, int len) {
 	unsigned char cmd[8];
 
 	memset((void *) &cmd[0], 0, 8);
 	cmd[0] = MODE_SENSE;
+	cmd[1] = dbd;
 	cmd[2] = modepage;
 	cmd[4] = len;
 
@@ -1115,6 +1055,8 @@ sd_do_mode_sense6(struct scsi_device *sdp, struct scsi_request *SRpnt,
 	SRpnt->sr_sense_buffer[2] = 0;
 	SRpnt->sr_data_direction = SCSI_DATA_READ;
 
+	memset((void *) buffer, 0, len);
+
 	scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
 		      len, SD_TIMEOUT, SD_MAX_RETRIES);
 
@@ -1135,7 +1077,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
 	 * We have to start carefully: some devices hang if we ask
 	 * for more than is available.
 	 */
-	res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 4);
+	res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 4);
 
 	/*
 	 * Second attempt: ask for page 0
@@ -1143,13 +1085,13 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
 	 * Sense Key 5: Illegal Request, Sense Code 24: Invalid field in CDB.
 	 */
 	if (res)
-		res = sd_do_mode_sense6(sdp, SRpnt, 0, buffer, 4);
+		res = sd_do_mode_sense6(sdp, SRpnt, 0, 0, buffer, 4);
 
 	/*
 	 * Third attempt: ask 255 bytes, as we did earlier.
 	 */
 	if (res)
-		res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 255);
+		res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 255);
 
 	if (res) {
 		printk(KERN_WARNING
@@ -1163,6 +1105,65 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
 	}
 }
 
+/*
+ * sd_read_cache_type - called only from sd_init_onedisk()
+ */
+static void
+sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
+		   struct scsi_request *SRpnt, unsigned char *buffer) {
+	struct scsi_device *sdp = sdkp->device;
+	int len = 0, res;
+
+	const int dbd = 0x08;	   /* DBD */
+	const int modepage = 0x08; /* current values, cache page */
+
+	/* cautiously ask */
+	res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, 4);
+
+	if (res == 0) {
+		/* that went OK, now ask for the proper length */
+		len = buffer[0] + 1;
+		if (len > 128)
+			len = 128;
+		res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, len);
+	}
+
+	if (res == 0 && buffer[3] + 6 < len) {
+		const char *types[] = {
+			"write through", "none", "write back",
+			"write back, no read (daft)"
+		};
+		int ct = 0;
+		int offset = buffer[3] + 4; /* start of mode page */
+
+		sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
+		sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
+
+		ct =  sdkp->RCD + 2*sdkp->WCE;
+
+		printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
+		       diskname, types[ct]);
+	} else {
+		if (res == 0 ||
+		    (status_byte(res) == CHECK_CONDITION
+		     && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
+		     && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
+		     /* ASC 0x24 ASCQ 0x00: Invalid field in CDB */
+		     && SRpnt->sr_sense_buffer[12] == 0x24
+		     && SRpnt->sr_sense_buffer[13] == 0x00)) {
+			printk(KERN_NOTICE "%s: cache data unavailable\n",
+			       diskname);
+		} else {
+			printk(KERN_ERR "%s: asking for cache data failed\n",
+			       diskname);
+		}
+		printk(KERN_ERR "%s: assuming drive cache: write through\n",
+		       diskname);
+		sdkp->WCE = 0;
+		sdkp->RCD = 0;
+	}
+}
+
 /**
  *	sd_init_onedisk - called the first time a new disk is seen,
  *	performs disk spin up, read_capacity, etc.
@@ -1208,15 +1209,20 @@ sd_init_onedisk(struct scsi_disk * sdkp, struct gendisk *disk)
 	sdkp->device->sector_size = 512;
 	sdkp->media_present = 1;
 	sdkp->write_prot = 0;
+	sdkp->WCE = 0;
+	sdkp->RCD = 0;
 
 	sd_spinup_disk(sdkp, disk->disk_name, SRpnt, buffer);
-	sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);
 
 	if (sdkp->media_present)
 		sd_read_capacity(sdkp, disk->disk_name, SRpnt, buffer);
 	
 	if (sdp->removable && sdkp->media_present)
 		sd_read_write_protect_flag(sdkp, disk->disk_name, SRpnt, buffer);
+	/* without media there is no reason to ask;
+	   moreover, some devices react badly if we do */
+	if (sdkp->media_present)
+		sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);
 		
 	SRpnt->sr_device->ten = 1;
 	SRpnt->sr_device->remap = 1;