Subject: Bug in multiple controller support in MSCP driver (+fix)
Index:	sys/pdpuba/ra.c 2.11BSD

Description:
	The multiple controller support in the MSCP (ra.c) driver only
	works with the first controller.  The first access to a drive
	on additional controller will crash the system.

Repeat-By:
	Add a second MSCP controller with a drive attached.  Attempt to
	create a file system on the drive.

Fix:
	The problem was in not clearing the controller number when using
	the "dkunit()" macro.

	The patch below will fix the problem by adding a mask of 7 after
	the two uses of dkunit().
--------------------------------------------------------------------------
*** /sys/pdpuba/ra.c.old	Sun Sep 22 08:40:02 1991
--- /sys/pdpuba/ra.c	Wed Dec 18 01:02:09 1991
***************
*** 14,19 ****
--- 14,24 ----
  
  /* 
   * ra.c - MSCP Driver
+  * Date:	Dec  18 1991
+  * The controller number (bits 6 and 7 of the minor device) were not
+  * being masked off after using dkunit().  This caused a crash when 
+  * the controller number was other than 0.
+  *
   * Date:	Sep  22 1991
   * The read and write entries were removed as part of implementing the 
   * common rawread and rawwrite routines.
***************
*** 436,442 ****
  	int s;
  
  	/* Is disk online */
! 	if ((disk = sc->sc_drives[dkunit(bp)]) == NULL || disk->ra_dsize <= 0L)
  		goto bad;
  
  	/* Valid block in device partition */
--- 441,447 ----
  	int s;
  
  	/* Is disk online */
! 	if ((disk = sc->sc_drives[dkunit(bp) & 7]) == NULL || disk->ra_dsize <= 0L)
  		goto bad;
  
  	/* Valid block in device partition */
***************
*** 551,557 ****
  		goto out;
  	mp->m_cmdref = (unsigned)bp;	/* pointer to get back */
  	mp->m_opcode = bp->b_flags & B_READ ? M_O_READ : M_O_WRITE;
! 	mp->m_unit = dkunit(bp);
  	disk = sc->sc_drives[mp->m_unit];
  	temp = bp->b_blkno + disk->ra_size[minor(bp->b_dev) & 7].blkoff;
  	mp->m_lbn_l = loint(temp);
--- 556,562 ----
  		goto out;
  	mp->m_cmdref = (unsigned)bp;	/* pointer to get back */
  	mp->m_opcode = bp->b_flags & B_READ ? M_O_READ : M_O_WRITE;
! 	mp->m_unit = dkunit(bp) & 7;
  	disk = sc->sc_drives[mp->m_unit];
  	temp = bp->b_blkno + disk->ra_size[minor(bp->b_dev) & 7].blkoff;
  	mp->m_lbn_l = loint(temp);