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firewire: ohci: fix crashes with TSB43AB23 on 64bit systems
Unsurprisingly, Texas Instruments TSB43AB23 exhibits the same behaviour as TSB43AB22/A in dual buffer IR DMA mode: If descriptors are located at physical addresses above the 31 bit address range (2 GB), the controller will overwrite random memory. With luck, this merely prevents video reception. With only a little less luck, the machine crashes. We use the same workaround here as with TSB43AB22/A: Switch off the dual buffer capability flag and use packet-per-buffer IR DMA instead. Another possible workaround would be to limit the coherent DMA mask to 31 bits. In Linux 2.6.33, this change serves effectively only as documentation since dual buffer mode is not used for any controller anymore. But somebody might want to re-enable it in the future to make use of features of dual buffer DMA that are not available in packet-per-buffer mode. In Linux 2.6.32 and older, this update is vital for anyone with this controller, more than 2 GB RAM, a 64 bit kernel, and FireWire video or audio applications. We have at least four reports: http://bugzilla.kernel.org/show_bug.cgi?id=13808 http://marc.info/?l=linux1394-user&m=126154279004083 https://bugzilla.redhat.com/show_bug.cgi?id=552142 http://marc.info/?l=linux1394-user&m=126432246128386 Reported-by: Paul Johnson Reported-by: Ronneil Camara Reported-by: G Zornetzer Reported-by: Mark Thompson Cc: stable@kernel.org Signed-off-by:Stefan Richter <stefanr@s5r6.in-berlin.de>