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From
SubjectRe: PCMCIA Interupt problems (2.2.17)
Date
In article <877laedgxv.wl@monster.bigfoot.com>,
YH Gian <yhgian@bigfoot.com> wrote:
>Thanks!
>>
>> This is a known bug; it is listed in the BUGS file. I've spent a lot
>> of time trying to track it down but I haven't figured out what the
>> problem is.
>
> I am not very familiar with what is going on with pccard
>interrupts but if the IRQs don't get through, why does the Network
>card still work after the suspend although it complains of the
>interrupts dropped ? The same can't be said for the modem card though.

Many (but not all) network drivers will actually check the state of the
send/receive buffers on timeouts etc, and will basically "correct" for
lost interrupts.

It doesn't work very well even in theory (performance is horrible, but
you often won't notice on a laptop where most of what you do is fairly
slow anyway), and it simply will not work at all on some cards that do
not have much of a buffer (ie if you lose interrupts you lose all the
packets).

Oh, and some drivers don't even try very hard: instead of trying to
recover packets on timeouts they try to just reset the card and start
over. Which is a perfectly reasonable thing to do, actually.

You might even get the serial thing to work if you can get it into
polled mode (do we even support this any more? I know we used to support
an interrupt-less serial card back in the -92 timeframe. Badly, but
still).

In any case it's pure luck that it works even as well as it seems to do.
Your network card may be limping along, but it could be worse.

Linus

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