Not sure how it came to this situation, but the following commit is
partly contained in our version of the code. Some lines had not been
removed, tough...

  commit c80c41767eb101e9dbd8393d8cca7764b4e248a4
  Author: Aaron Plattner <aplattner@nvidia.com>
  Date:   Mon Oct 25 22:01:32 2010 -0700

    os: Fix BigReq ignoring when another request is pending

    Commit cf88363db0ebb42df7cc286b85d30d7898aea840 fixed the handling of
    BigReq requests that are way too large and handles the case where the
    read() syscall returns a short read.  However, it neglected to handle
    the case where it returns a long read, which happens when the client
    has another request in the queue after the bogus large one.

    Handle the long read case by subtracting the smaller of 'needed' and
    'gotnow' from oci->ignoreBytes.  If needed < gotnow, simply subtract
    the two, leaving gotnow equal to the number of extra bytes read.
    Since the code immediately following the (oci->ignoreBytes > 0) block
    tries to handle the next request, advance oci->bufptr immediately
    instead of setting oci->lenLastReq and letting the next call to
    ReadRequestFromClient do it.

    Fixes the XTS pChangeKeyboardMapping-3 test.

             CASES TESTS  PASS UNSUP UNTST NOTIU  WARN   FIP  FAIL UNRES  UNIN ABORT
    -Xproto    122   389   367     2    19     0     0     0     1     0     0     0
    +Xproto    122   389   368     2    19     0     0     0     0     0     0     0
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>