Re: In-tree version of new FireWire drivers available

From: David Moore
Date: Wed Jan 24 2007 - 16:36:03 EST


Kristian HÃgsberg wrote:

- Always allocate a page for headers and a page for the payload.

This method would not really be acceptable as a replacement for video1394, since video buffers can often be many tens of megabytes. Doubling the space requirement would be a big deal and may cause the allocation to fail.

How about this solution:

Give userspace the option of specifying the exact size of the received ISO packets. If userspace provides this, you can allocate the dual buffer descriptors appropriately.

If userspace does not know the exact size of the received ISO packets or does not specify it, then use dual buffer descriptors for only the first packet, and use regular buffer fill for the remaining packets.

I suggest this strategy because I can't think of an application that needs all the packet headers, yet doesn't know the exact size of the packet. Is there such an application?

-David
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