USB Memory support quick hack

Hi all,

I write a small patch to support USB memory without adding an entry
 to da_quirk_table[].

Idea in this patch is disable SYNC_CACHE when synchronize cache failed.
This new feature is controled by "kern.cam.da.fallback_no_sync_cache".

I test my USB memory (TOSHIBA TransMemory) which is not in da_quirk_table[].

[test resutl]
# sysctl kern.cam.da.fallback_no_sync_cache
kern.cam.da.fallback_no_sync_cache: 0
# umass1: TOSHIBA TransMemory, rev 2.00/1.00, addr 2
da2 at umass-sim1 bus 1 target 0 lun 0
da2: <TOSHIBA TransMemory 1.00> Removable Direct Access SCSI-0 device 
da2: 1.000MB/s transfers
da2: 240MB (492544 512 byte sectors: 64H 32S/T 240C)
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
# sysctl -w kern.cam.da.fallback_no_sync_cache=1
kern.cam.da.fallback_no_sync_cache: 0 -> 1
# umass1: TOSHIBA TransMemory, rev 2.00/1.00, addr 2
da2 at umass-sim1 bus 1 target 0 lun 0
da2: <TOSHIBA TransMemory 1.00> Removable Direct Access SCSI-0 device 
da2: 1.000MB/s transfers
da2: 240MB (492544 512 byte sectors: 64H 32S/T 240C)
umass1: Phase Error, residue = 0
(da2:umass-sim1:1:0:0): Synchronize cache failed, status == 0x4, scsi status == 0x0
(da2:umass-sim1:1:0:0): Disable SYNC_CACHE

If you have interest my patch, please try it.

Thanks,
-------
YAMAMOTO Shigeru	<shigeru_at_iij.ad.jp>

Index: sys/cam/scsi/scsi_da.c
===================================================================
RCS file: /share/cvsup/FreeBSD/current/usr/src/sys/cam/scsi/scsi_da.c,v
retrieving revision 1.173
diff -u -r1.173 scsi_da.c
--- sys/cam/scsi/scsi_da.c	5 Jan 2005 22:34:34 -0000	1.173
+++ sys/cam/scsi/scsi_da.c	28 Jan 2005 08:19:15 -0000
_at__at_ -348,6 +348,7 _at__at_
 
 static int da_retry_count = DA_DEFAULT_RETRY;
 static int da_default_timeout = DA_DEFAULT_TIMEOUT;
+static int da_fallback_no_sync_cache = 0;
 
 SYSCTL_NODE(_kern_cam, OID_AUTO, da, CTLFLAG_RD, 0,
             "CAM Direct Access Disk driver");
_at__at_ -357,6 +358,9 _at__at_
 SYSCTL_INT(_kern_cam_da, OID_AUTO, default_timeout, CTLFLAG_RW,
            &da_default_timeout, 0, "Normal I/O timeout (in seconds)");
 TUNABLE_INT("kern.cam.da.default_timeout", &da_default_timeout);
+SYSCTL_INT(_kern_cam_da, OID_AUTO, fallback_no_sync_cache, CTLFLAG_RW,
+           &da_fallback_no_sync_cache, 0, "Fallback to no sync cache");
+TUNABLE_INT("kern.cam.da.fallback_no_sync_cache", &da_fallback_no_sync_cache);
 
 /*
  * DA_ORDEREDTAG_INTERVAL determines how often, relative
_at__at_ -498,6 +502,11 _at__at_
 				       "== 0x%x, scsi status == 0x%x\n",
 				       ccb->csio.ccb_h.status,
 				       ccb->csio.scsi_status);
+				if (da_fallback_no_sync_cache) {
+					xpt_print_path(periph->path);
+					printf("Disable SYNC_CACHE\n");
+					softc->quirks |= DA_Q_NO_SYNC_CACHE;
+				}
 			}
 		}
 
_at__at_ -669,6 +678,11 _at__at_
 				printf("Synchronize cache failed, status "
 				       "== 0x%x, scsi status == 0x%x\n",
 				       csio.ccb_h.status, csio.scsi_status);
+				if (da_fallback_no_sync_cache) {
+					xpt_print_path(periph->path);
+					printf("Disable SYNC_CACHE\n");
+					softc->quirks |= DA_Q_NO_SYNC_CACHE;
+				}
 			}
 		}
 	}
_at__at_ -1818,6 +1832,11 _at__at_
 				printf("Synchronize cache failed, status "
 				       "== 0x%x, scsi status == 0x%x\n",
 				       ccb.ccb_h.status, ccb.csio.scsi_status);
+				if (da_fallback_no_sync_cache) {
+					xpt_print_path(periph->path);
+					printf("Disable SYNC_CACHE\n");
+					softc->quirks |= DA_Q_NO_SYNC_CACHE;
+				}
 			}
 		}