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

[Pavel Machek]

On Sun 2007-12-30 21:46:50, Ingo Molnar wrote:
> 
> * Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> 
> > > So the current plan is to go with an io_delay=udelay default in v2.6.25, 
> > > to give this a migration window, and io_delay=none in v2.6.26 [and a 
> > > complete removal of arch/x86/kernel/io_delay.c], once the _p() uses are 
> > > fixed up. This is gradual enough to notice any regressions we care about 
> > > and also makes it nicely bisectable and gradual.
> > 
> > You will break systems if you blindly go around disabling _p delays 
> > for ISA and LPC bus devices. The DEC Hinote laptops for example are 
> > well known for requiring the correct ISA and other keyboard controller 
> > delays. I don't expect anyone to test with a hinote or see it until it 
> > hits Debian or similar 'low resource' friendly devices.
> 
> well, using io_delay=udelay is not 'blindly disabling'. io_delay=none 
> would be the end goal, once all _p() API uses are eliminated by 
> transformation. In drivers/ alone that's more than 1000 callsites, so 
> it's quite frequently used, and wont go away overnight.

IOW elimination of broken inb_p()/outb_p() interfaces is the ultimate
goal. Agreed.

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