[realtek] Question: Rx Ring Buffers in the rtl8139 module

[Donald Becker]

On Thu, 29 Aug 2002 joerg.beyer@email.de wrote:

> I understand that all received packets are put in a ring buffer, while
> more efficient NIC drivers
                     ^^^^^^^

No, more efficient NIC __hardware__ puts the each packet into its own
buffer.  The rtl8139 (before the much better "C+", which still isn't
commonly available) only has the hardware to receive into into a single
ring buffer.

> build a descriptor based buffer architeture. Is it possilble, or has anybody
> tried, to use a descriptor based buffer layout with the 8139 card?

It's not possible.
The hardware only supports a single region for receive.  As each packet
comes in, it is appended to the ring.

> Which is the most simple example of a descriptor based Rx Buffer NIC module?

No other driver is similar to the rtl8139.

A simple driver is the VIA-rhine driver.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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