[U-Boot] [PATCH] net: cpsw: am335x: Drop constant link checking from rx/tx path's

Tom Rini trini at ti.com
Tue Aug 26 17:14:05 CEST 2014


On Mon, Aug 25, 2014 at 11:26:19AM +0200, Stefan Roese wrote:

> We noticed on the DXR2 platform (AM335x with a SMSC LAN9303 switch connected
> to the CPSW MAC) that the network performance in U-Boot is quite poor. Only
> when the transfer is started without a cable connected, and the cable is
> plugged after the first timeout "T" occured, an increased in performance
> can be seen. Debugging has revealed, that the cpsw driver has constant
> link checking builtin into the rx and tx functions. This results in the
> bad performance and seems to be unnecessary. The link has already been
> checked in the init function, before the transfer is started. This usually
> is sufficient.
> 
> BTW: I have seen no other network driver in U-Boot so far, that constantly
> checks for link in the rx / tx functions.

Yes, this strongly feels like a bring-up sanity check thing that was
left in by accident.

-- 
Tom
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