Re: [netbsd-10] src bus_dma.9 copyedit

[Van Ly <van.ly%sdf.org@localhost>]

Valery Ushakov <uwe%stderr.spb.ru@localhost> writes:

> On Fri, Oct 04, 2024 at 18:58:39 +0000, Van Ly wrote:
>
>> => http://sdf.org/~van.ly/art/bus-dma-9-copyedit.jpeg
>
> I don't think so.  "Exclusive" here means that the given flag is
> mutually exclusive with another flag.  It doesn't make sense to
> combine nocache and prefetchable exclusive and that's what the
> highlighted sentences say.
>



I haven't made the cognitive effort.  The indenting in the presentation
and separation distance of tokens had my eyes wanting to group them that
way on skim reading, perhaps an xor flag demonstration gets the intended
point across succinctly



 1                      BUS_DMA_NOCACHE   This flag is a hint to machine-
 2                                        dependent code.  If possible, map the
 3                                        memory uncached.  This flag may be
 4                                        useful in the case that the memory
 5                                        cache causes unexpected behavior of the
 6                                        device.
 7 
 8                                        Exclusive with BUS_DMA_PREFETCHABLE.
 9                      BUS_DMA_PREFETCHABLE
10                                        This flag is a hint to machine-
11                                        dependent code.  If possible, map the
12                                        memory prefetchable/write-combining.
13 
14                                        Exclusive with BUS_DMA_NOCACHE.



-- 
vl