It's probably worth mentioning that since the interface between the CPU and GPU is running so fast (>1GHz), that it is probably 8b10b encoded, in some form. What this means is that anything that goes out on the bus first goes through a look-up table, of sorts, and the results are what is put on the bus. This is done for the simple reason of trying to improve signal integrity at those speeds and not for any protection/encryption requirements. Formal 8b10b encoding ensures that there are always the same number of '1' and '0' signals across a bus... this helps keep down the current draw between subsequent transactions (at 1GHz, the period is 1nSec... imagine the amount of current needed to drive all zeros to all ones, at 1nSec, with an adequate eye-diagram opening to tell the difference... That would need drivers that were faster than PECL... i.e... LOTS of current)...
If anyone got the idea to physically probe the bus, one would first need to R.E. the 8b10b 'like' scheme before getting to the actual data, which might, in itself, be pre-encrypted... One would be able to tell, from early accesses, if the transactions looked like setup/config accesses, or garbage. Regards, Bruce Boettjer ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ free60-devel mailing list free60-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/free60-devel
