[openib-general] Re: [PATCH][16/26] IB/mthca: mem-free doorbell record writing

[Michael S. Tsirkin]

Quoting r. Roland Dreier <roland at topspin.com>:
> Subject: Re: [PATCH][16/26] IB/mthca: mem-free doorbell record writing
> 
>     Jeff> Well, we don't just add code to "hope and pray" for an event
>     Jeff> that nobody is sure can even occur...
> 
> The hardware requires that if the record is written in two 32-bit
> chunks, then they must be written in order.  Of course the hardware
> probably won't be reading just as we're writing, so almost all of the
> time we won't notice the problem.

Its not necessarily related to reads. writes must arrive in
order, even if the card is not reading at that time.

-- 
MST - Michael S. Tsirkin