From: Anton Vorontsov <[email protected]> Date: Wed, 30 Jun 2010 20:39:13 +0400
> MPC8313ECE says: > > "For TOE=1 huge or jumbo frames, the data required to generate the > checksum may exceed the 2500-byte threshold beyond which the controller > constrains itself to one memory fetch every 256 eTSEC system clocks. > > This throttling threshold is supposed to trigger only when the > controller has sufficient data to keep transmit active for the duration > of the memory fetches. The state machine handling this threshold, > however, fails to take large TOE frames into account. As a result, > TOE=1 frames larger than 2500 bytes often see excess delays before start > of transmission." > > This patch implements the workaround as suggested by the errata > document, i.e.: > > "Limit TOE=1 frames to less than 2500 bytes to avoid excess delays due to > memory throttling. > When using packets larger than 2700 bytes, it is recommended to turn TOE > off." > > To be sure, we limit the TOE frames to 2500 bytes, and do software > checksumming instead. > > Signed-off-by: Anton Vorontsov <[email protected]> Applied. _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
