Re: kern/42225 (can't read data from SuperTop IDE Bridge (umass))

[Markus W Kilbinger <mk%kilbi.de@localhost>]

Hi!

After several months I've reactivated my SuperTop hardware:

  umass1 at uhub5 port 4 configuration 1 interface 0
  umass1: Super Top USB 2.0  IDE DEVICE, rev 2.00/2.01, addr 3
  umass1: using SCSI over Bulk-Only
  scsibus1 at umass1: 2 targets, 1 lun per target
  sd1 at scsibus1 target 0 lun 0: <ST316002, 3A, 0\0000> disk fixed
  sd1: 149 GB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 312581808 sectors

on my -current machine

  NetBSD 5.99.25 (Q) #8: Sun Apr  4 21:43:29 MEST 2010  .../amd64/compile/Q 
amd64

, but it didn't work! I could see the dmesg, fdisk and disklabel
output, but reading more than 1 block seems to fail (it works at/with
other machines / os's).

So, looking at the source and the initial and final patches I've made
the following change:

Index: umass.c
===================================================================
RCS file: /cvsroot/src/sys/dev/usb/umass.c,v
retrieving revision 1.138
diff -u -r1.138 umass.c
--- umass.c     13 Feb 2010 02:16:51 -0000      1.138
+++ umass.c     4 Apr 2010 20:07:22 -0000
@@ -1179,7 +1179,7 @@
                DIF(UDMASS_BBB, umass_bbb_dump_csw(sc, &sc->csw));
 
                residue = UGETDW(sc->csw.dCSWDataResidue);
-               if (residue < sc->transfer_datalen - sc->transfer_actlen)
+               if (residue != sc->transfer_datalen - sc->transfer_actlen)
                        residue = sc->transfer_datalen - sc->transfer_actlen;
 
                /* Translate weird command-status signatures. */


With this little change my usb disk works! (?)
I only have (tested) some usb memory sticks as other umasses and did
not see any problem with this change/patch.

If not requiring a quirk (for several usb ide bridges) what is residue
good for?

Comments?

Markus.