Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80I/O delay override.

[David P. Reed]

Windows these days does delays with timing loops or the scheduler.  It 
doesn't use a "port".  Also, Windows XP only supports machines that tend 
not to have timing problems that use delays.  Instead, if a device takes 
a while to respond, it has a "busy bit" in some port or memory slot that 
can be tested.

Almost all of the issues in Linux where _p operations are used are (or 
should be) historical - IMO.

Ondrej Zary wrote:
> On Tuesday 08 January 2008 02:38:15 David P. Reed wrote:
>   
> > H. Peter Anvin wrote:
> >     
> > > And shoot the designer of this particular microcontroller firmware.
> > >       
> > Well, some days I want to shoot the "designer" of the entire Wintel
> > architecture...  it's not exactly "designed" by anybody of course, and
> > today it's created largely by a collection of Taiwanese and Chinese ODM
> > firms, coupled with Microsoft WinHEC and Intel folks.  At least they
> > follow the rules and their ACPI and BIOS code say that they are using
> > port 80 very clearly if you use PnP and ACPI properly.  And in the old
> > days, you were "supposed" to use the system BIOS to talk to things like
> > the PIT that had timing issues, not write your own code.
> >     
>
> Does anyone know what port does Windows use? I'm pretty sure that it isn't 80h 
> as I run Windows 98 often with port 80h debug card inserted. The last POST 
> code set by BIOS usually remains on the display and only changes when BIOS 
> does something like suspend/resume. IIRC, there was a program that was able 
> to display temperature from onboard sensors on the port 80h display that's 
> integrated on some mainboards.
>
>   
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