Plextor drives are quite popular, and even though MMC-complaint, have a few
extra vendor-specific commands. This patch allows those commands, which fixes
cd burning on plextor drives.

Signed-off-by: Daniel Drake <dsd@gentoo.org>

--- linux/drivers/block/scsi_ioctl.c.orig	2004-12-03 13:50:10.720382720 +0000
+++ linux/drivers/block/scsi_ioctl.c	2004-12-03 13:52:00.414706648 +0000
@@ -186,6 +186,12 @@
 		safe_for_write(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL),
 		safe_for_write(GPCMD_LOAD_UNLOAD),
 		safe_for_write(GPCMD_SET_STREAMING),
+
+		/* PLEXTOR specific commands */
+		safe_for_read(0xEB), // get drive speeds
+		safe_for_read(0xF5), // read BPC
+		safe_for_write(0xE9), // set drivemode
+		safe_for_write(0xED), // set drivemode
 	};
 	unsigned char type = cmd_type[cmd[0]];