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SubjectRe: Updated 2.3.x job list (its getting shorter)
On Mon, 31 Jan 31 2000 around 09:04:53 -0600, Jeff Garzik wrote:
> On Sun, 30 Jan 2000, Jamie Lokier wrote:
> > How much hardware can do _ISA_ scatter/gather DMA?
>
> * allocate scatter-gather buffers
> * point hardware to buffer #1
> * in interrupt handler or bottom half:
> process buffer
> point hardware at buffer #2
>
> And now your old ISA hardware does scatter-gather.

This is not what I would call scatter-gather, my impression
was that with S-C you can give a link of buffers with arbitrary
size and location to the controller and it will write its
data from buffer to buffer each filling it to the given size.
Than, when the card if finished transfering its stuff,
say a frame, it signals you to do something usefull with it.

In your understanding (as i understand it :) ) each DMA capable
card it S-C.

Lets presume I have a card which needs to transfer 4MB. No
inbetween readyness interrupts, just a single one after the
4MB is completed... So how do we get this to S-C?

Okok, we can probably program the DMA controller to the first
S-C item, and a-wait its 'done' interrupt. But can we reprogram
the thing fast enough for the next S-C slice? /me think not...

Met vriendelijke groet,
Pauline Middelink
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For more details look at my website http://www.polyware.nl/~middelink

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