USB OHCI problems...

From: Barry Bouwsma (freebsd-misuser_at_remove-NOSPAM-to-reply.NOSPAM.dyndns.dk)
Date: 10/20/04

  • Next message: Simon L. Nielsen: "Re: [CFR] Specify the lock(1) timeout unit" 
    Date: Wed, 20 Oct 2004 18:12:47 +0200 (CEST)
To: freebsd-hackers@freebsd.org

    Apologies for this posting, as so far as I know it's a known
    issue that the USB OHCI code has some problems, or perhaps
    that there have been code commits in the last weeks so this
    is no longer a problem...

    Anyway, under FreeBSD-4 with kernel modules built 10.August
    from source that I believe is based on FreeBSD-5-current of
    that era, I'm seeing corruption of data read from umass
    devices attached to an OHCI controller card. Use of a UHCI
    controller card instead seems mostly free of problems.

    In comparison, I accessed the data with NetBSD-current of
    similar vintage, and in the files copied with the identical
    hardware, the data is intact.

    The point at which the corruption begins is at some multiple
    of 16384 bytes into the file. The corruption is not consistent,
    as it is less likely to occur when the machine is somewhat idle,
    and as the below shows, also occurs at different points into
    the same file.

    I haven't looked to see for how long this corruption is present
    (it's more than a few hundred bytes, at least) or how the file
    appears after this, or whether this corruption follows any
    particular pattern of the rest of the file.

    The below is `cmp' output under my FreeBSD, compared against
    the files previously downloaded with NetBSD (and verified that
    all the images are intact).

    /cdrom/dcim/100dscim/pict0681.jpg pict0681.jpg differ: char 524289, line 2284
    /cdrom/dcim/100dscim/pict0683.jpg pict0683.jpg differ: char 507905, line 2116
    /cdrom/dcim/100dscim/pict0684.jpg pict0684.jpg differ: char 1163265, line 3323
    /cdrom/dcim/100dscim/pict0685.jpg pict0685.jpg differ: char 294913, line 1402
    /cdrom/dcim/100dscim/pict0686.jpg pict0686.jpg differ: char 393217, line 1716
    /cdrom/dcim/100dscim/pict0687.jpg pict0687.jpg differ: char 753665, line 2606
    /cdrom/dcim/100dscim/pict0686.jpg pict0686.jpg differ: char 983041, line 3648

    This is just a sample -- note that the last line is the same file
    that I had previously `cmp'ed two lines above.

    In fairness, the files copied from NetBSD were done with the
    machine mostly idle, so I don't know if NetBSD suffers the
    same if I were pounding the machine.

    If this issue hasn't been handled, perhaps the fact that NetBSD
    doesn't seem to have problems might give someone some ideas as
    to where the problem might lie.

    As usual, apologies for the untimeliness of this, as well as
    my lack of detailed testing with fresh -current or with code
    fresher than two months ago.

    thanks
    barry bouwsma

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