Re: keyboard timeout

From: Alan Cox
Date: Thu Dec 02 2004 - 10:18:26 EST


On Iau, 2004-12-02 at 13:11, linux-os wrote:
> >From original IBM specification...
> "...8284A Clock generator clock generator supplies the multiphase
> clock signals that are needed to drive the microprocessor and
> the peripherals. Its base frequency is 14.31818 MHz....."

And the ISA bus side is 8.33Mhz (4.77Mhz on original PC, 6Mhz on
original
XT, originally 10MHz put rapidly fixed back to 8 on some others).

The 1Mhz clock to the keyboard controller is where the required delays
for talking to it come from. Similarly for the other low frequency parts
hacked into the PC (DMA etc).

Our keyboard code appears correct in all respects so you probably want
to adjust the various pc_kbd delays or look to see if you can find one
missing that matters to your PC as I doubt anyone using a post 1990
computer can actually help debug it because their hardware simply won't
care.

Alan

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