Re: [2*PATCH] alpha I/O access and mb()

Abramo Bagnara
2000-12-09T12:03:26Z

Gérard Roudier wrote:
>
>
> Based on that, let me claim that most of blind barriers inserted this way
> are useless (thus sob-optimal) and may band-aid useful barriers that are
> missing. The result is subtle bugs, hidden most of the time, that we will
> have to suffer for decades.
>
> The only way to do things right regarding ordering it to have device
> drivers _aware_ of such issues. Now, if we are happy with broken portable
> or platform-independant drivers that rely on broken hidden ordering
> alchemy rather than on correctness, then it is another story.

I see perfectly your point and this is the reason why we have
__raw_write[bwlq] in 2.4, but write[bwlq] expected semantic is to ensure
that write *happens* and are visible by other agents.

You can tell me that almost nobody uses __raw_write now and this is bad
and I agree with you, but sometime this is not a perfect world ;-)