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SubjectRe: Possible critical VIA vt82c686a chip bug (private question)
On 26 Oct 2000, Yoann Vandoorselaere wrote:
> Vojtech Pavlik <vojtech@suse.cz> writes:
[Snipped...]

../drivers/block/ide.c, line 162, on version 2.2.17 does bad things
to the timer. It writes 0 to the control-word for timer 0. This
does the following:

o Selects timer 0.
o Latches the timer.
o Selects mode 0.
o Programs it to a 16 bit counter.

The result is a latched (stopped) counter. Bits 5 and 4 should have been
selected. Then you read bits 0-7 from 0x40, followed by bits 8-15 from
the same port.

Also, there is no spin-lock protecting access to these ports. If anybody
else is mucking with the timer, all bets are off.

Cheers,
Dick Johnson

Penguin : Linux version 2.2.17 on an i686 machine (801.18 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.


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