Messages in this thread | | | Date | Thu, 17 Jan 2008 16:55:13 +1030 | From | David Newall <> | Subject | Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. |
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Alan Cox wrote: >> If the hardware required an intermediate junk I/O, that would be a >> reason to do one, but it doesn't, does it? It requires a delay. It's >> written thus in all of the application notes. >> > > And the only instruction that is synchronized to the bus in question is > an I/O instruction. >
This is a timing issue, isn't it? How are we synchronising, other than by delaying for a (bus-dependant) period? The characteristics of each bus are known so a number can be assigned for "one bus cycle", without having to use the bus.
>> Wrong again. Of course one knows how long the delay should be. The bus >> speed is known. >> > > Wrong again. ISA bus speed is neither defined precisely, nor visible in a > system portable fashion. >
You say, "system portable," but I think you mean, "automatically determined." We don't have to define this value automatically, if that's so hard to do. We can use a tunable kernel-parameter.
> I'm so glad you have nothing better to do than troll
I'm not trolling. You know this is true because many people perceive this to be a problem. I'm working on fixing it. Not all Linux problems are solvable by diving into code, and there is anecdotal evidence to believe this one has big performance considerations. I don't understand why you are opposed to even talking about it.
> if you > actually wrote code I'd be worried it might get into something people > used.
Speaking of writing code: I remember working on a bluetooth Oops. Lacking the hardware, I went to you for advice on how to get it before someone for testing. You never replied.
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