Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

From: H. Peter Anvin
Date: Sun Dec 16 2007 - 21:10:22 EST


Rene Herman wrote:
On 16-12-07 16:22, Ingo Molnar wrote:

looks good to me. Could you please also provide three more controls that i suggested earlier:

- a boot option enabling/disabling the udelay based code
- a .config method of enabling/disabling the udelay based code
- a sysctl to toggle it

if we want to clean this all up we'll need as many controls as possible.

This version does the boot and the .config option but not the sysctl. It makes for clumsy code and I don't believe it provides for much added value as soon as you have the boot option. I am moreover not completely confident about things such as paravirt liking the possibility of the native_io_delay being changed out from under them at unpredictable times.


Incidentally, I had the thought earlier today that port 0xf0 might be a suitable delay port. It is used only by the 387-emulating-a-287 hack for IRQ 13, which Linux doesn't use on 486+.

-hpa
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