Messages in this thread | | | Date | Sun, 16 Dec 2007 18:05:16 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. |
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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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