On Fri, Oct 27, 2017 at 11:15:34AM -0400, Mouse wrote: > Heh. Well, reading the x86 bus_dma implementation (amd64 doesn't seem > to have a separate bus_dma implementation of its own) leads me to think > it has no such issues; all POSTREAD does there is copy from the bounce > buffer (if the transfer is bounced) and issue an lfence memory barrier. > (Hmm, I wonder if the memory barrier needs to be before the memcpy....)
This was discussed at length on irc over the weekend, and the conclusion seems to be "yes". With a side order of "why can't architecture manuals ever be clear about these things?" -- David A. Holland dholl...@netbsd.org
