sanei_scsi_cmd / snapscan / Prisa640S

From: Christian Nassau (
Date: Wed Jan 10 2001 - 02:19:39 PST

  • Next message: Christian Nassau: "snapscan"

    I'm currently trying to get an Acer ScanPrisa640S (patched atp870u
    scsi driver, kernel version 2.2.16) working with a (modified) snapscan
    backend. I had the following problem...

      aborting scanimage in the middle of a scan with CRTL-C leads
      to a system lock (requiring an instant reboot).

    ...and have found that sanei_scsi_cmd(..) only protects the
    scsi read and write instructions individually against user
    breaks. The SCSI-Programming-FAQ (dated 1997) that I have says
    that the **pair** (write/read) has to be protected, because
    otherwise very bad things will happen... (depending on the
    kernel version)...

    ... so, I've created a wrapper "sanei_scsi_protected_cmd(..)" and
    made snapscan use this function, and -- alas! -- userbreaks are
    safe now.

    Couldn't one make sanei_scsi_cmd(..) protected by default, or at
    least provide a protected alternative? (or make the Makefile decide
    which one to install, based on the kernel version?)

    Christian Nassau


    Fachbereich Mathematik (12)
    AG 8.1, Zi.814
    Johann Wolfgang Goethe-Universit"at
    Robert-Mayer-Str. 6-10
    D-60054 Frankfurt/M
    --- Germany ---

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