Re: [PATCH] stmmac: fix driver features

[David Miller <davem@davemloft.net>]

From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
Date: Fri, 10 Feb 2012 08:08:54 +0100

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