Re: [dpdk-dev] [PATCH] librte_ethdev: extend dpdk api led control to query capability

[Thomas Monjalon <thomas@monjalon.net>]

08/01/2020 14:20, Ferruh Yigit:
> On 1/8/2020 1:06 PM, Thomas Monjalon wrote:
> > 08/01/2020 13:59, Ferruh Yigit:
> >> But for dev_ops, instead of having another capabilities indicator, which
> >> requires PMDs to keep this synchronized, I think it is better if we can self
> >> contain this information within dev_ops, like not implementing dev_ops would
> >> mean it is not supported, this way it is easier to maintain and less error prone.
> > 
> > It means the dev_ops is resetted at init if a device does not support the feature.
> > It is against having const dev_ops.
> 
> I didn't get your comment.
> For example getting FW version, I am saying instead of keeping another piece of
> information to say if it is supported by device/driver, better to grasp this
> from if the driver implemented 'fw_version_get' dev_ops or not.

I like this approach.
Capabilities should be expressed by setting the function pointer or not (NULL).
But a driver may support a feature for a subset of devices.
If a device does not support a feature, the function pointer must be set to NULL.
The only issue is having dev_ops as a const struct.