[PATCH] ATAPI MO drive support

From: Pascal Schmidt <der.eremit@email.de>

The below patch is needed to support ATAPI MO drives in 2.6. ide-scsi
doesn't work any more for this, so ide-cd has to take over the job of
running the MO drive. Without this, there is no way to write to an
ATAPI MO drive.

This patch has been discussed with Linus and Jens already around test9
time and it was agreed this is the right way to go about it. I have
rediffed it against 2.6.0. Compiles, runs, works just fine for me.

drivers/cdrom/cdrom.c

@@ -426,7 +426,8 @@ int cdrom_open(struct cdrom_device_info *cdi, struct inode *ip, struct file *fp)
 	if ((fp->f_flags & O_NONBLOCK) && (cdi->options & CDO_USE_FFLAGS))
 		ret = cdi->ops->open(cdi, 1);
 	else {
-		if ((fp->f_mode & FMODE_WRITE) && !CDROM_CAN(CDC_DVD_RAM))
+		if ((fp->f_mode & FMODE_WRITE) &&
+		    !(CDROM_CAN(CDC_DVD_RAM) || CDROM_CAN(CDC_MO_DRIVE)))
 			return -EROFS;
 
 		ret = open_for_data(cdi);

drivers/ide/ide-cd.c

@@ -2242,6 +2242,7 @@ static int cdrom_read_toc(ide_drive_t *drive, struct request_sense *sense)
 		struct atapi_toc_header hdr;
 		struct atapi_toc_entry  ent;
 	} ms_tmp;
+	long last_written;
 
 	if (toc == NULL) {
 		/* Try to allocate space. */
@@ -2261,6 +2262,13 @@ static int cdrom_read_toc(ide_drive_t *drive, struct request_sense *sense)
 	if (CDROM_STATE_FLAGS(drive)->toc_valid)
 		return 0;
 
+	/* Try to get the total cdrom capacity. */
+	stat = cdrom_read_capacity(drive, &toc->capacity, sense);
+	if (stat)
+		toc->capacity = 0x1fffff;
+
+	set_capacity(drive->disk, toc->capacity * SECTORS_PER_FRAME);
+
 	/* First read just the header, so we know how long the TOC is. */
 	stat = cdrom_read_tocentry(drive, 0, 1, 0, (char *) &toc->hdr,
 				    sizeof(struct atapi_toc_header), sense);
@@ -2368,13 +2376,11 @@ static int cdrom_read_toc(ide_drive_t *drive, struct request_sense *sense)
 	toc->xa_flag = (ms_tmp.hdr.first_track != ms_tmp.hdr.last_track);
 
 	/* Now try to get the total cdrom capacity. */
-	stat = cdrom_get_last_written(cdi, (long *) &toc->capacity);
-	if (stat || !toc->capacity)
-		stat = cdrom_read_capacity(drive, &toc->capacity, sense);
-	if (stat)
-		toc->capacity = 0x1fffff;
-
-	set_capacity(drive->disk, toc->capacity * SECTORS_PER_FRAME);
+	stat = cdrom_get_last_written(cdi, &last_written);
+	if (!stat && last_written) {
+		toc->capacity = last_written;
+		set_capacity(drive->disk, toc->capacity * SECTORS_PER_FRAME);
+	}
 
 	/* Remember that we've read this stuff. */
 	CDROM_STATE_FLAGS(drive)->toc_valid = 1;
@@ -3215,7 +3221,8 @@ int ide_cdrom_setup (ide_drive_t *drive)
 
 	nslots = ide_cdrom_probe_capabilities (drive);
 
-	if (CDROM_CONFIG_FLAGS(drive)->dvd_ram)
+	if (CDROM_CONFIG_FLAGS(drive)->dvd_ram ||
+	    CDROM_CONFIG_FLAGS(drive)->mo_drive)
 		set_disk_ro(drive->disk, 0);
 
 #if 0