To apply:
       cd /usr/src/sys/dev/atapi
       patch -p0 < atapi.patch

Index: acd.c
===================================================================
RCS file: /cvs/src/sys/dev/atapi/acd.c,v
retrieving revision 1.29
retrieving revision 1.32
diff -u -r1.29 -r1.32
--- acd.c       1997/10/18 10:37:06     1.29
+++ acd.c       1998/07/12 01:20:20     1.32
@@ -1101,6 +1093,7 @@
{
       struct atapi_read_cd_capacity_data rdcap;
       struct atapi_read_cd_capacity cmd;
+       int result;

       if (acd->ad_link->quirks & AQUIRK_NOCAPACITY) {
               /*
@@ -1125,8 +1118,15 @@
        * If the command works, interpret the result as a 4 byte
        * number of blocks and a blocksize
        */
-       if (atapi_exec_cmd(acd->ad_link, &cmd, sizeof(cmd),
-           &rdcap, sizeof(rdcap), B_READ, 0) != 0) {
+       result = atapi_exec_cmd(acd->ad_link, &cmd, sizeof(cmd),
+                               &rdcap, sizeof(rdcap), B_READ, 0);
+       if (result != 0) {
+               u_int8_t error = result >> 8;
+               /* Get the sense key and check for an illegal request */
+               if ((error >> 4) == ATAPI_SK_ILLEGAL_REQUEST) {
+                       acd->ad_link->quirks |= AQUIRK_NOCAPACITY;
+                       return acd_size(acd, flags);
+               }
               ATAPI_DEBUG_PRINT(("ATAPI_READ_CD_CAPACITY failed\n"));
               return 0;
       }
Index: atapiconf.c
===================================================================
RCS file: /cvs/src/sys/dev/atapi/atapiconf.c,v
retrieving revision 1.21
diff -u -r1.21 atapiconf.c
--- atapiconf.c 1998/01/02 18:22:07     1.21
+++ atapiconf.c 1998/08/04 21:42:18
@@ -354,6 +357,9 @@
               if ((flags & A_POLLED) != 0)
                       atapi_free_pkt(pkt);
       }
+
+       if ((pkt->status & ERROR) && (pkt->error))
+            status |= pkt->error << 8;

       return status;
}