Bug 14333

 
 aha0 is found and probed correctly but fails when probing for
 attached devices. Output during boot is:
 
 aha0 at 0x330-0x333 irq 11 drq 5 on isa
 aha0: AHA-1540/1542 64 head BIOS FW Rev. 0.6 (ID=41) SCSI Host Adapter, SCSI ID 
 7, 16 CCBs
 Waiting 15 seconds for SCSI devices to settle
 aha0: AHA-1540A detected, compensating
 aha0: AHA-1540A detected, compensating
 aha0: AHA-1540A detected, compensating
 aha0: AHA-1540A detected, compensating
 aha0: AHA-1540A detected, compensating
 aha0: AHA-1540A detected, compensating
 
 then the machine just hangs.
 
 works with FreeBSD 2.x, output of "boot -v" in 2.2.8:
 aha0: Rev 41 (AHA-154x[AB]) V0.6, enabling residuals, target ops

Fix: 

disabling residuals in aha.c cured the problem on my machine.
 I've no clue about the consequences of the modification I did,
 but if possible I'd like to have this as the default for the
 GENERIC kernel, since it make installation possible with this
 controller. On the other hand residuals IMHO aren't the real
 source of the problem since obviously they worked in 2.2.8.
 
 Context diff of sources from 3.1-RELEASE follows:
 
 *** aha.c       Wed Jan 20 07:21:26 1999
 --- aha.c-orig  Thu Oct 14 20:55:46 1999
 ***************
 *** 242,249 ****
         aha->unit = unit;
         aha->tag = tag;
         aha->bsh = bsh;
 !       aha->ccb_sg_opcode = INITIATOR_SG_CCB_WRESID;
 !       aha->ccb_ccb_opcode = INITIATOR_CCB_WRESID;
   
         if (aha->unit != AHA_TEMP_UNIT) {
                 aha_softcs[unit] = aha;
 --- 242,249 ----
         aha->unit = unit;
         aha->tag = tag;
         aha->bsh = bsh;
 !       aha->ccb_ccb_opcode = INITIATOR_CCB;
 !       aha->ccb_sg_opcode = INITIATOR_SG_CCB;
   
         if (aha->unit != AHA_TEMP_UNIT) {
                 aha_softcs[unit] = aha;
How-To-Repeat:  
 Boot with Install-floppies of FreeBSD 3.x or 4.0-current