Messages in this thread | | | Date | Sat, 18 Jan 2014 17:05:09 +0100 | From | Stefan Richter <> | Subject | Re: [PATCH] firewire: Enable remote DMA above 4 GB |
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On Jan 18 Stefan Richter wrote: > This makes all of a machine's memory accessible to remote debugging via > FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link > layer controllers. > > This requires actual support by the controller. The only ones currently > known to support it are Agere/LSI FW643. Most if not all other OHCI-1394 > controllers do not implement the optional Physical Upper Bound register. > With them, RDMA will continue to be limited to the lowermost 4 GB. [...]
PS, this patch does not switch remote DMA on. It only increases the range of remote access to all memory (instead of just 4 GB) _when_ remote DMA was switched on by other means. The latter is achieved by setting CONFIG_FIREWIRE_OHCI_REMOTE_DMA, or by a module parameter introduced by commit 8bc588e0e585 of linux1394.git, or if the physical DMA filter is opened through firewire-sbp2. -- Stefan Richter -=====-====- ---= =--=- http://arcgraph.de/sr/
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