possible fix for strange USB sticks / SD card readers

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

As it was reported repeatedly, some USB sticks do not work on NetBSD,
often a "Generic HBA error" is reported in the kernel log.
There seem to be different kinds of misbehavior which cause this
symptom. Finally I got one strange USB stick between my fingers,
this one answers the SCSI "Request Sense" after an unsupported
command with an USB pipe stall.
Here is a patch which makes the code tolerate this behavior in
certain cases. With that, the stick I got works properly.

Can those of you with other non-working USB sticks (or SD card
readers which sometimes use similar controller chips) try
the patch and report whether it helps?

best regards
Matthias


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# HG changeset patch
# Parent da9a11f068ab6496d09db5a3e644e115f78523bc
diff -r da9a11f068ab -r 935aaa80dad2 sys/dev/usb/umass_scsipi.c
--- a/sys/dev/usb/umass_scsipi.c        Fri Aug 10 22:18:40 2012 +0200
+++ b/sys/dev/usb/umass_scsipi.c        Fri Aug 10 22:45:50 2012 +0200
@@ -487,7 +487,10 @@
        default:
                DPRINTF(UDMASS_SCSI, ("%s: Autosense failed, status %d\n",
                        device_xname(sc->sc_dev), status));
-               xs->error = XS_DRIVER_STUFFUP;
+               if (xs->xs_control & XS_CTL_IGNORE_ILLEGAL_REQUEST)
+                       xs->error = XS_NOERROR;
+               else
+                       xs->error = XS_DRIVER_STUFFUP;
                break;
        }