Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 669 insertions, 0 deletions

diff --git a/drivers/usb/storage/datafab.c b/drivers/usb/storage/datafab.c
new file mode 100644
index 000000000000..54e3e6c7ecd8
--- /dev/null
+++ b/drivers/usb/storage/datafab.c
@@ -0,0 +1,669 @@
+/* Driver for Datafab USB Compact Flash reader
+ *
+ * $Id: datafab.c,v 1.7 2002/02/25 00:40:13 mdharm Exp $
+ *
+ * datafab driver v0.1:
+ *
+ * First release
+ *
+ * Current development and maintenance by:
+ *   (c) 2000 Jimmie Mayfield (mayfield+datafab@sackheads.org)
+ *
+ *   Many thanks to Robert Baruch for the SanDisk SmartMedia reader driver
+ *   which I used as a template for this driver.
+ *
+ *   Some bugfixes and scatter-gather code by Gregory P. Smith 
+ *   (greg-usb@electricrain.com)
+ *
+ *   Fix for media change by Joerg Schneider (js@joergschneider.com)
+ *
+ * Other contributors:
+ *   (c) 2002 Alan Stern <stern@rowland.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * This driver attempts to support USB CompactFlash reader/writer devices
+ * based on Datafab USB-to-ATA chips.  It was specifically developed for the 
+ * Datafab MDCFE-B USB CompactFlash reader but has since been found to work 
+ * with a variety of Datafab-based devices from a number of manufacturers.
+ * I've received a report of this driver working with a Datafab-based
+ * SmartMedia device though please be aware that I'm personally unable to
+ * test SmartMedia support.
+ *
+ * This driver supports reading and writing.  If you're truly paranoid,
+ * however, you can force the driver into a write-protected state by setting
+ * the WP enable bits in datafab_handle_mode_sense().  See the comments
+ * in that routine.
+ */
+
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+
+#include "usb.h"
+#include "transport.h"
+#include "protocol.h"
+#include "debug.h"
+#include "datafab.h"
+
+static int datafab_determine_lun(struct us_data *us,
+				 struct datafab_info *info);
+
+
+static inline int
+datafab_bulk_read(struct us_data *us, unsigned char *data, unsigned int len) {
+	if (len == 0)
+		return USB_STOR_XFER_GOOD;
+
+	US_DEBUGP("datafab_bulk_read:  len = %d\n", len);
+	return usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
+			data, len, NULL);
+}
+
+
+static inline int
+datafab_bulk_write(struct us_data *us, unsigned char *data, unsigned int len) {
+	if (len == 0)
+		return USB_STOR_XFER_GOOD;
+
+	US_DEBUGP("datafab_bulk_write:  len = %d\n", len);
+	return usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
+			data, len, NULL);
+}
+
+
+static int datafab_read_data(struct us_data *us,
+			     struct datafab_info *info,
+			     u32 sector,
+			     u32 sectors)
+{
+	unsigned char *command = us->iobuf;
+	unsigned char *buffer;
+	unsigned char  thistime;
+	unsigned int totallen, alloclen;
+	int len, result;
+	unsigned int sg_idx = 0, sg_offset = 0;
+
+	// we're working in LBA mode.  according to the ATA spec, 
+	// we can support up to 28-bit addressing.  I don't know if Datafab
+	// supports beyond 24-bit addressing.  It's kind of hard to test 
+	// since it requires > 8GB CF card.
+	//
+	if (sectors > 0x0FFFFFFF)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	if (info->lun == -1) {
+		result = datafab_determine_lun(us, info);
+		if (result != USB_STOR_TRANSPORT_GOOD)
+			return result;
+	}
+
+	totallen = sectors * info->ssize;
+
+	// Since we don't read more than 64 KB at a time, we have to create
+	// a bounce buffer and move the data a piece at a time between the
+	// bounce buffer and the actual transfer buffer.
+
+	alloclen = min(totallen, 65536u);
+	buffer = kmalloc(alloclen, GFP_NOIO);
+	if (buffer == NULL)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	do {
+		// loop, never allocate or transfer more than 64k at once
+		// (min(128k, 255*info->ssize) is the real limit)
+
+		len = min(totallen, alloclen);
+		thistime = (len / info->ssize) & 0xff;
+
+		command[0] = 0;
+		command[1] = thistime;
+		command[2] = sector & 0xFF;
+		command[3] = (sector >> 8) & 0xFF;
+		command[4] = (sector >> 16) & 0xFF;
+
+		command[5] = 0xE0 + (info->lun << 4);
+		command[5] |= (sector >> 24) & 0x0F;
+		command[6] = 0x20;
+		command[7] = 0x01;
+
+		// send the read command
+		result = datafab_bulk_write(us, command, 8);
+		if (result != USB_STOR_XFER_GOOD)
+			goto leave;
+
+		// read the result
+		result = datafab_bulk_read(us, buffer, len);
+		if (result != USB_STOR_XFER_GOOD)
+			goto leave;
+
+		// Store the data in the transfer buffer
+		usb_stor_access_xfer_buf(buffer, len, us->srb,
+				 &sg_idx, &sg_offset, TO_XFER_BUF);
+
+		sector += thistime;
+		totallen -= len;
+	} while (totallen > 0);
+
+	kfree(buffer);
+	return USB_STOR_TRANSPORT_GOOD;
+
+ leave:
+	kfree(buffer);
+	return USB_STOR_TRANSPORT_ERROR;
+}
+
+
+static int datafab_write_data(struct us_data *us,
+			      struct datafab_info *info,
+			      u32 sector,
+			      u32 sectors)
+{
+	unsigned char *command = us->iobuf;
+	unsigned char *reply = us->iobuf;
+	unsigned char *buffer;
+	unsigned char thistime;
+	unsigned int totallen, alloclen;
+	int len, result;
+	unsigned int sg_idx = 0, sg_offset = 0;
+
+	// we're working in LBA mode.  according to the ATA spec, 
+	// we can support up to 28-bit addressing.  I don't know if Datafab
+	// supports beyond 24-bit addressing.  It's kind of hard to test 
+	// since it requires > 8GB CF card.
+	//
+	if (sectors > 0x0FFFFFFF)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	if (info->lun == -1) {
+		result = datafab_determine_lun(us, info);
+		if (result != USB_STOR_TRANSPORT_GOOD)
+			return result;
+	}
+
+	totallen = sectors * info->ssize;
+
+	// Since we don't write more than 64 KB at a time, we have to create
+	// a bounce buffer and move the data a piece at a time between the
+	// bounce buffer and the actual transfer buffer.
+
+	alloclen = min(totallen, 65536u);
+	buffer = kmalloc(alloclen, GFP_NOIO);
+	if (buffer == NULL)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	do {
+		// loop, never allocate or transfer more than 64k at once
+		// (min(128k, 255*info->ssize) is the real limit)
+
+		len = min(totallen, alloclen);
+		thistime = (len / info->ssize) & 0xff;
+
+		// Get the data from the transfer buffer
+		usb_stor_access_xfer_buf(buffer, len, us->srb,
+				&sg_idx, &sg_offset, FROM_XFER_BUF);
+
+		command[0] = 0;
+		command[1] = thistime;
+		command[2] = sector & 0xFF;
+		command[3] = (sector >> 8) & 0xFF;
+		command[4] = (sector >> 16) & 0xFF;
+
+		command[5] = 0xE0 + (info->lun << 4);
+		command[5] |= (sector >> 24) & 0x0F;
+		command[6] = 0x30;
+		command[7] = 0x02;
+
+		// send the command
+		result = datafab_bulk_write(us, command, 8);
+		if (result != USB_STOR_XFER_GOOD)
+			goto leave;
+
+		// send the data
+		result = datafab_bulk_write(us, buffer, len);
+		if (result != USB_STOR_XFER_GOOD)
+			goto leave;
+
+		// read the result
+		result = datafab_bulk_read(us, reply, 2);
+		if (result != USB_STOR_XFER_GOOD)
+			goto leave;
+
+		if (reply[0] != 0x50 && reply[1] != 0) {
+			US_DEBUGP("datafab_write_data:  Gah! "
+				  "write return code: %02x %02x\n",
+				  reply[0], reply[1]);
+			result = USB_STOR_TRANSPORT_ERROR;
+			goto leave;
+		}
+
+		sector += thistime;
+		totallen -= len;
+	} while (totallen > 0);
+
+	kfree(buffer);
+	return USB_STOR_TRANSPORT_GOOD;
+
+ leave:
+	kfree(buffer);
+	return USB_STOR_TRANSPORT_ERROR;
+}
+
+
+static int datafab_determine_lun(struct us_data *us,
+				 struct datafab_info *info)
+{
+	// Dual-slot readers can be thought of as dual-LUN devices.
+	// We need to determine which card slot is being used.
+	// We'll send an IDENTIFY DEVICE command and see which LUN responds...
+	//
+	// There might be a better way of doing this?
+
+	static unsigned char scommand[8] = { 0, 1, 0, 0, 0, 0xa0, 0xec, 1 };
+	unsigned char *command = us->iobuf;
+	unsigned char *buf;
+	int count = 0, rc;
+
+	if (!us || !info)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	memcpy(command, scommand, 8);
+	buf = kmalloc(512, GFP_NOIO);
+	if (!buf)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	US_DEBUGP("datafab_determine_lun:  locating...\n");
+
+	// we'll try 3 times before giving up...
+	//
+	while (count++ < 3) {
+		command[5] = 0xa0;
+
+		rc = datafab_bulk_write(us, command, 8);
+		if (rc != USB_STOR_XFER_GOOD) {
+			rc = USB_STOR_TRANSPORT_ERROR;
+			goto leave;
+		}
+
+		rc = datafab_bulk_read(us, buf, 512);
+		if (rc == USB_STOR_XFER_GOOD) {
+			info->lun = 0;
+			rc = USB_STOR_TRANSPORT_GOOD;
+			goto leave;
+		}
+
+		command[5] = 0xb0;
+
+		rc = datafab_bulk_write(us, command, 8);
+		if (rc != USB_STOR_XFER_GOOD) {
+			rc = USB_STOR_TRANSPORT_ERROR;
+			goto leave;
+		}
+
+		rc = datafab_bulk_read(us, buf, 512);
+		if (rc == USB_STOR_XFER_GOOD) {
+			info->lun = 1;
+			rc = USB_STOR_TRANSPORT_GOOD;
+			goto leave;
+		}
+
+		msleep(20);
+	}
+
+	rc = USB_STOR_TRANSPORT_ERROR;
+
+ leave:
+	kfree(buf);
+	return rc;
+}
+
+static int datafab_id_device(struct us_data *us,
+			     struct datafab_info *info)
+{
+	// this is a variation of the ATA "IDENTIFY DEVICE" command...according
+	// to the ATA spec, 'Sector Count' isn't used but the Windows driver
+	// sets this bit so we do too...
+	//
+	static unsigned char scommand[8] = { 0, 1, 0, 0, 0, 0xa0, 0xec, 1 };
+	unsigned char *command = us->iobuf;
+	unsigned char *reply;
+	int rc;
+
+	if (!us || !info)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	if (info->lun == -1) {
+		rc = datafab_determine_lun(us, info);
+		if (rc != USB_STOR_TRANSPORT_GOOD)
+			return rc;
+	}
+
+	memcpy(command, scommand, 8);
+	reply = kmalloc(512, GFP_NOIO);
+	if (!reply)
+		return USB_STOR_TRANSPORT_ERROR;
+
+	command[5] += (info->lun << 4);
+
+	rc = datafab_bulk_write(us, command, 8);
+	if (rc != USB_STOR_XFER_GOOD) {
+		rc = USB_STOR_TRANSPORT_ERROR;
+		goto leave;
+	}
+
+	// we'll go ahead and extract the media capacity while we're here...
+	//
+	rc = datafab_bulk_read(us, reply, 512);
+	if (rc == USB_STOR_XFER_GOOD) {
+		// capacity is at word offset 57-58
+		//
+		info->sectors = ((u32)(reply[117]) << 24) | 
+				((u32)(reply[116]) << 16) |
+				((u32)(reply[115]) <<  8) | 
+				((u32)(reply[114])      );
+		rc = USB_STOR_TRANSPORT_GOOD;
+		goto leave;
+	}
+
+	rc = USB_STOR_TRANSPORT_ERROR;
+
+ leave:
+	kfree(reply);
+	return rc;
+}
+
+
+static int datafab_handle_mode_sense(struct us_data *us,
+				     struct scsi_cmnd * srb, 
+				     int sense_6)
+{
+	static unsigned char rw_err_page[12] = {
+		0x1, 0xA, 0x21, 1, 0, 0, 0, 0, 1, 0, 0, 0
+	};
+	static unsigned char cache_page[12] = {
+		0x8, 0xA, 0x1, 0, 0, 0, 0, 0, 0, 0, 0, 0
+	};
+	static unsigned char rbac_page[12] = {
+		0x1B, 0xA, 0, 0x81, 0, 0, 0, 0, 0, 0, 0, 0
+	};
+	static unsigned char timer_page[8] = {
+		0x1C, 0x6, 0, 0, 0, 0
+	};
+	unsigned char pc, page_code;
+	unsigned int i = 0;
+	struct datafab_info *info = (struct datafab_info *) (us->extra);
+	unsigned char *ptr = us->iobuf;
+
+	// most of this stuff is just a hack to get things working.  the
+	// datafab reader doesn't present a SCSI interface so we
+	// fudge the SCSI commands...
+	//
+
+	pc = srb->cmnd[2] >> 6;
+	page_code = srb->cmnd[2] & 0x3F;
+
+	switch (pc) {
+	   case 0x0:
+		US_DEBUGP("datafab_handle_mode_sense:  Current values\n");
+		break;
+	   case 0x1:
+		US_DEBUGP("datafab_handle_mode_sense:  Changeable values\n");
+		break;
+	   case 0x2:
+		US_DEBUGP("datafab_handle_mode_sense:  Default values\n");
+		break;
+	   case 0x3:
+		US_DEBUGP("datafab_handle_mode_sense:  Saves values\n");
+		break;
+	}
+
+	memset(ptr, 0, 8);
+	if (sense_6) {
+		ptr[2] = 0x00;		// WP enable: 0x80
+		i = 4;
+	} else {
+		ptr[3] = 0x00;		// WP enable: 0x80
+		i = 8;
+	}
+
+	switch (page_code) {
+	   default:
+		// vendor-specific mode
+		info->sense_key = 0x05;
+		info->sense_asc = 0x24;
+		info->sense_ascq = 0x00;
+		return USB_STOR_TRANSPORT_FAILED;
+
+	   case 0x1:
+		memcpy(ptr + i, rw_err_page, sizeof(rw_err_page));
+		i += sizeof(rw_err_page);
+		break;
+
+	   case 0x8:
+		memcpy(ptr + i, cache_page, sizeof(cache_page));
+		i += sizeof(cache_page);
+		break;
+
+	   case 0x1B:
+		memcpy(ptr + i, rbac_page, sizeof(rbac_page));
+		i += sizeof(rbac_page);
+		break;
+
+	   case 0x1C:
+		memcpy(ptr + i, timer_page, sizeof(timer_page));
+		i += sizeof(timer_page);
+		break;
+
+	   case 0x3F:		// retrieve all pages
+		memcpy(ptr + i, timer_page, sizeof(timer_page));
+		i += sizeof(timer_page);
+		memcpy(ptr + i, rbac_page, sizeof(rbac_page));
+		i += sizeof(rbac_page);
+		memcpy(ptr + i, cache_page, sizeof(cache_page));
+		i += sizeof(cache_page);
+		memcpy(ptr + i, rw_err_page, sizeof(rw_err_page));
+		i += sizeof(rw_err_page);
+		break;
+	}
+
+	if (sense_6)
+		ptr[0] = i - 1;
+	else
+		((__be16 *) ptr)[0] = cpu_to_be16(i - 2);
+	usb_stor_set_xfer_buf(ptr, i, srb);
+
+	return USB_STOR_TRANSPORT_GOOD;
+}
+
+static void datafab_info_destructor(void *extra)
+{
+	// this routine is a placeholder...
+	// currently, we don't allocate any extra memory so we're okay
+}
+
+
+// Transport for the Datafab MDCFE-B
+//
+int datafab_transport(struct scsi_cmnd * srb, struct us_data *us)
+{
+	struct datafab_info *info;
+	int rc;
+	unsigned long block, blocks;
+	unsigned char *ptr = us->iobuf;
+	static unsigned char inquiry_reply[8] = {
+		0x00, 0x80, 0x00, 0x01, 0x1F, 0x00, 0x00, 0x00
+	};
+
+	if (!us->extra) {
+		us->extra = kmalloc(sizeof(struct datafab_info), GFP_NOIO);
+		if (!us->extra) {
+			US_DEBUGP("datafab_transport:  Gah! "
+				  "Can't allocate storage for Datafab info struct!\n");
+			return USB_STOR_TRANSPORT_ERROR;
+		}
+		memset(us->extra, 0, sizeof(struct datafab_info));
+		us->extra_destructor = datafab_info_destructor;
+  		((struct datafab_info *)us->extra)->lun = -1;
+	}
+
+	info = (struct datafab_info *) (us->extra);
+
+	if (srb->cmnd[0] == INQUIRY) {
+		US_DEBUGP("datafab_transport:  INQUIRY.  Returning bogus response");
+		memcpy(ptr, inquiry_reply, sizeof(inquiry_reply));
+		fill_inquiry_response(us, ptr, 36);
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	if (srb->cmnd[0] == READ_CAPACITY) {
+		info->ssize = 0x200;  // hard coded 512 byte sectors as per ATA spec
+		rc = datafab_id_device(us, info);
+		if (rc != USB_STOR_TRANSPORT_GOOD)
+			return rc;
+
+		US_DEBUGP("datafab_transport:  READ_CAPACITY:  %ld sectors, %ld bytes per sector\n",
+			  info->sectors, info->ssize);
+
+		// build the reply
+		// we need the last sector, not the number of sectors
+		((__be32 *) ptr)[0] = cpu_to_be32(info->sectors - 1);
+		((__be32 *) ptr)[1] = cpu_to_be32(info->ssize);
+		usb_stor_set_xfer_buf(ptr, 8, srb);
+
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	if (srb->cmnd[0] == MODE_SELECT_10) {
+		US_DEBUGP("datafab_transport:  Gah! MODE_SELECT_10.\n");
+		return USB_STOR_TRANSPORT_ERROR;
+	}
+
+	// don't bother implementing READ_6 or WRITE_6.
+	//
+	if (srb->cmnd[0] == READ_10) {
+		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
+			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
+
+		blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));
+
+		US_DEBUGP("datafab_transport:  READ_10: read block 0x%04lx  count %ld\n", block, blocks);
+		return datafab_read_data(us, info, block, blocks);
+	}
+
+	if (srb->cmnd[0] == READ_12) {
+		// we'll probably never see a READ_12 but we'll do it anyway...
+		//
+		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
+			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
+
+		blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
+			 ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));
+
+		US_DEBUGP("datafab_transport:  READ_12: read block 0x%04lx  count %ld\n", block, blocks);
+		return datafab_read_data(us, info, block, blocks);
+	}
+
+	if (srb->cmnd[0] == WRITE_10) {
+		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
+			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
+
+		blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));
+
+		US_DEBUGP("datafab_transport:  WRITE_10: write block 0x%04lx  count %ld\n", block, blocks);
+		return datafab_write_data(us, info, block, blocks);
+	}
+
+	if (srb->cmnd[0] == WRITE_12) {
+		// we'll probably never see a WRITE_12 but we'll do it anyway...
+		//
+		block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
+			((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));
+
+		blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
+			 ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));
+
+		US_DEBUGP("datafab_transport:  WRITE_12: write block 0x%04lx  count %ld\n", block, blocks);
+		return datafab_write_data(us, info, block, blocks);
+	}
+
+	if (srb->cmnd[0] == TEST_UNIT_READY) {
+		US_DEBUGP("datafab_transport:  TEST_UNIT_READY.\n");
+		return datafab_id_device(us, info);
+	}
+
+	if (srb->cmnd[0] == REQUEST_SENSE) {
+		US_DEBUGP("datafab_transport:  REQUEST_SENSE.  Returning faked response\n");
+
+		// this response is pretty bogus right now.  eventually if necessary
+		// we can set the correct sense data.  so far though it hasn't been
+		// necessary
+		//
+		memset(ptr, 0, 18);
+		ptr[0] = 0xF0;
+		ptr[2] = info->sense_key;
+		ptr[7] = 11;
+		ptr[12] = info->sense_asc;
+		ptr[13] = info->sense_ascq;
+		usb_stor_set_xfer_buf(ptr, 18, srb);
+
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	if (srb->cmnd[0] == MODE_SENSE) {
+		US_DEBUGP("datafab_transport:  MODE_SENSE_6 detected\n");
+		return datafab_handle_mode_sense(us, srb, 1);
+	}
+
+	if (srb->cmnd[0] == MODE_SENSE_10) {
+		US_DEBUGP("datafab_transport:  MODE_SENSE_10 detected\n");
+		return datafab_handle_mode_sense(us, srb, 0);
+	}
+
+	if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL) {
+		// sure.  whatever.  not like we can stop the user from
+		// popping the media out of the device (no locking doors, etc)
+		//
+		return USB_STOR_TRANSPORT_GOOD;
+	}
+
+	if (srb->cmnd[0] == START_STOP) {
+		/* this is used by sd.c'check_scsidisk_media_change to detect
+		   media change */
+		US_DEBUGP("datafab_transport:  START_STOP.\n");
+		/* the first datafab_id_device after a media change returns
+		   an error (determined experimentally) */
+		rc = datafab_id_device(us, info);
+		if (rc == USB_STOR_TRANSPORT_GOOD) {
+			info->sense_key = NO_SENSE;
+			srb->result = SUCCESS;
+		} else {
+			info->sense_key = UNIT_ATTENTION;
+			srb->result = SAM_STAT_CHECK_CONDITION;
+		}
+		return rc;
+	}
+
+	US_DEBUGP("datafab_transport:  Gah! Unknown command: %d (0x%x)\n",
+		  srb->cmnd[0], srb->cmnd[0]);
+	info->sense_key = 0x05;
+	info->sense_asc = 0x20;
+	info->sense_ascq = 0x00;
+	return USB_STOR_TRANSPORT_FAILED;
+}