Subject: Re: bus_space_barrier shortcomings
To: None <>
From: Jason R Thorpe <>
List: tech-kern
Date: 11/16/2000 08:13:35
On Thu, Nov 16, 2000 at 04:03:44PM -0000, wrote:

 > Huh?  I'll admit that bus_space_barrier lacks some of the 
 > flexibility of the barriers available on some architectures,
 > but a BUS_SPACE_BARRIER_WRITE barrier should be sufficient
 > to ensure the write completes.  If completion of the memory
 > operation is not enough to acknowledge the interrupt, your
 > hardware is broken to the point that it is impossible to 
 > write a driver for it on any machine.

As defined BUS_SPACE_BARRIER_WRITE merely requires that all other writes
complete before the one after the barrier.

        -- Jason R. Thorpe <>