Messages in this thread |  | | | Date | Tue, 1 Jan 2008 18:32:38 +0100 | | From | Christer Weinigel <> | | Subject | Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. |
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On Tue, 1 Jan 2008 17:43:38 +0100 Ingo Molnar <mingo@elte.hu> wrote:
> if someone runs a fresh new kernel on an ancient device then timings > _will_ change a bit, no matter what we do. Alignments change, the > compiler output will change (old compilers get deprecated so a new > compiler might have to be picked), cache effects change - and this is > inevitable. The important thing is to not eliminate the delays - but > we sure dont have to keep them cycle accurate (we couldnt even if we > wanted to). The only way to get the _exact same_ behavior is to not > change the kernel at all.
What I'm afraid is that udelay will be significantly slower, which might hit anything that does a lot of gettimeofday calls (poking at the PIT timer) on embedded 386/486 systems. On the other hand, those systems might not want to upgrade to 2.6 anyway.
And why do people keep buying HP hardware? HP seem to be quite Linux-unfriendly on the desktop [1] and on their laptops. Apparently HP doesn't even bother to try Linux on any of their non-server systems.
[1] Try running Linux on a HP DC7700 machine, there seems to be a lot of magic stuff in those machines that doesn't work well with Linux. They had some ACPI crap that stopped FC7 from booting without a lot of magic PCI access options and audio still does not work.
/Christer
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