Re: [PATCH] i386, x86_64 Initial PAT implementation

Eric W. Biederman
2005-08-30T16:06:37Z

Andi Kleen <ak@suse.de> writes:

> On Tuesday 30 August 2005 17:20, Eric W. Biederman wrote:
>
>> Right. To the best of my understanding problem aliases are either
>> uncached/write-back or write-combine/write-back. I don't think
>> uncached/write-combine can cause problems. My basic reason for
>
> Well it can if one driver expects the mapping to be uncached and the
> other to be WC. The WC one might blast over the other one badly.
>
> Also the architecture defines all attribute conflicts to be undefined
> and it's better to not rely on undefined behaviour because that could
> break quite badly on a future microarchitecture.

Agreed. It is better.

My assessment was only to show that the immediate danger of data
corruption or problems isn't very high, even if someone does goof.

Eric