Re: [PATCH] stmmac: fix driver features

From: Giuseppe CAVALLARO <redacted>
Date: Fri, 10 Feb 2012 08:08:54 +0100

Hello David

On 2/9/2012 9:35 PM, David Miller wrote:

quoted

This is not the purpose of the fix_features method, it's meant to
ensure that the settings are valid.

It's not meant to "catch up" with settings you store in the internal
datastructures of your driver.

You need to do this at probe time, where the initial ->hw_features
and ->features values are set.

Initially the driver HW features are indeed set in the probe but in the
stmmac_open function, after looking at the HW cap reg, some parameters,
for example the HW csum, can be overridden and the
netdev_update_features is called. IIUC the netdev_update_features calls
the driver's ndo_fix_features. For this reason I improved the
stmmac_fix_feature function to cover more setting. Anyway, if I cannot
use this function I should move from the open to the probe the logic to
manage the MAC identification and HW cap register. What do you suggest?

You should not be determining chip features in your open method,
such work belongs in your device probe.