THIS IS PRE-PRE-RELEASE SOFTWARE - USE AT YOUR OWN RISK!

Hopefully if you have a 274x/284x that functions using the unmodified
driver, it will continue to function.  It appears that some machines
use a different interrupt type than I assumed, however - this patch
attempts to detect and correct those.
:ja

*** aha274x.c-rel5	Sun Sep 18 14:47:32 1994
--- aha274x.c	Sun Sep 18 14:52:46 1994
***************
*** 1,5 ****
  /*
!  *  @(#)aha274x.c 1.25 94/09/06 jda
   *
   *  Adaptec 274x device driver for Linux.
   *  Copyright (c) 1994 The University of Calgary Department of Computer Science.
--- 1,5 ----
  /*
!  *  @(#)aha274x.c 1.26 94/09/18 jda
   *
   *  Adaptec 274x device driver for Linux.
   *  Copyright (c) 1994 The University of Calgary Department of Computer Science.
***************
*** 153,159 ****
  
  struct aha274x_host {
  	int base;					/* card base address */
! 	int unpause;					/* value for HCNTRL */
  	volatile Scsi_Cmnd *SCB_array[AHA274X_MAXSCB];	/* active commands */
  };
  
--- 153,160 ----
  
  struct aha274x_host {
  	int base;					/* card base address */
! 	int startup;					/* intr type check */
! 	volatile int unpause;				/* value for HCNTRL */
  	volatile Scsi_Cmnd *SCB_array[AHA274X_MAXSCB];	/* active commands */
  };
  
***************
*** 437,442 ****
--- 438,454 ----
  	base = p->base;
  
  	/*
+ 	 *  Check the startup flag - if no commands have been queued,
+ 	 *  we probably have the interrupt type set wrong.  Unpausing
+ 	 *  the sequencer will reload the host control register.
+ 	 */
+ 	if (p->startup) {
+ 		p->unpause ^= 0x8;
+ 		UNPAUSE_SEQUENCER(p);
+ 		return;
+ 	}
+ 
+ 	/*
  	 *  Handle all the interrupt sources - especially for SCSI
  	 *  interrupts, we won't get a second chance at them.
  	 */
***************
*** 906,914 ****
  
  	/*
  	 *  The interrupt trigger is different depending
! 	 *  on whether the card is EISA or VL-bus.
  	 */
  	p->unpause = (type != T_274X ? 0x2 : 0xa);
  
  	/*
  	 *  Register IRQ with the kernel _after_ the host information
--- 918,931 ----
  
  	/*
  	 *  The interrupt trigger is different depending
! 	 *  on whether the card is EISA or VL-bus - sometimes.
! 	 *  The startup variable will be cleared once the first
! 	 *  command is queued, and is checked in the isr to
! 	 *  try and detect when the interrupt type is set
! 	 *  incorrectly, triggering an interrupt immediately.
  	 */
  	p->unpause = (type != T_274X ? 0x2 : 0xa);
+ 	p->startup = !0;
  
  	/*
  	 *  Register IRQ with the kernel _after_ the host information
***************
*** 994,1000 ****
  	return("Adaptec AHA274x/284x (EISA/VL-bus -> Fast SCSI) "
  	       AHA274X_SEQ_VERSION "/"
  	       AHA274X_H_VERSION "/"
! 	       "1.25");
  }
  
  int aha274x_command(Scsi_Cmnd *cmd)
--- 1011,1017 ----
  	return("Adaptec AHA274x/284x (EISA/VL-bus -> Fast SCSI) "
  	       AHA274X_SEQ_VERSION "/"
  	       AHA274X_H_VERSION "/"
! 	       "1.26");
  }
  
  int aha274x_command(Scsi_Cmnd *cmd)
***************
*** 1119,1124 ****
--- 1136,1147 ----
  	 *  paused a minimal amount of time.
  	 */
  	aha274x_buildscb(p, cmd, &scb);
+ 
+ 	/*
+ 	 *  Clear the startup flag - we can now legitimately
+ 	 *  expect interrupts.
+ 	 */
+ 	p->startup = 0;
  
  	/*
  	 *  This is a critical section, since we don't want the