The theory here is that the device may not be properly initializing its on-chip memory, leaving some of it in a parity errored state, and enabling parity check may result in the device blowing up.

Error message:
http://hup.hu/old/images/trey/work/clevo_core_duo/S3600052.JPG

Fix: Relevant threads:

http://marc.theaimsgroup.com/?l=dragonfly-kernel&m=109967161431080&w=2

See this commit:

http://www.dragonflybsd.org/cvsweb/src/sys/bus/firewire/fwohci_pci.c?rev=1.16&content-type=text/x-cvsweb-markup

Or:



+       /*
+        * Clear PCIM_CMD_MWRICEN as per FreeBSD/1.20, but note that the
+        * problem may have been related to SERR and PERR being
+        * unconditionally enabled in that rev.
+        *
+        * Do not change the SERRESPEN or PERRESPEN bits.  Use the BIOS
+        * values (probably off).  This crashes some machines in
fwohci_init().
+        *
+        * The theory here is that the device may not be properly
initializing
+        * its on-chip memory, leaving some of it in a parity errored
state,
+        * and enabling parity check may result in the device blowing
up.
+        * It's also possible that some hardware is just plain broken.
OpenBSD
+        * does not turn on SERRESPEN or PERRESPEN so we won't either.
+        */
        cmd = pci_read_config(self, PCIR_COMMAND, 2);
-       cmd |= PCIM_CMD_MEMEN | PCIM_CMD_BUSMASTEREN | PCIM_CMD_MWRICEN
|
-               PCIM_CMD_SERRESPEN | PCIM_CMD_PERRESPEN;
-#if 1  /* for broken hardware */
+       cmd |= PCIM_CMD_MEMEN | PCIM_CMD_BUSMASTEREN;
        cmd &= ~PCIM_CMD_MWRICEN;
-       cmd &= ~(PCIM_CMD_SERRESPEN | PCIM_CMD_PERRESPEN);
-#endif
        pci_write_config(self, PCIR_COMMAND, cmd, 2);

        /*--eYvGKBtip12U9eUPEWikXWPfjq4Rpw8ronq51o9SSnbjVJkK
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--- fwohci_pci.c.orig   Mon Mar 27 22:11:47 2006
+++ fwohci_pci.c        Mon Mar 27 22:36:47 2006
@@ -240,13 +240,23 @@
        int olatency, latency, ocache_line, cache_line;
        uint16_t cmd;
How-To-Repeat: Boot with unpatched kernel.