[dpdk-dev] [RFC] some questions for speed_capa usage

[dpdk-dev] [RFC] some questions for speed_capa usage

[oulijun]

Hi,


The 'speed_capa' will be reported in rte_eth_dev_info_get API. How 
should users use the field?

1) The driver reports only the capabilities supported by the NIC, and 
users only obtain the capabilities.
Maybe, there is a case that a rate bit in 'speed_capa' is not supported 
by the current transmission medium,
such as, copper cable optical modules and optical interface modules.

2) The field is used only to inform users of the speed_capa supported by 
the current transmission medium.
And users set the fixed speed or auto-negotiation by using 'link_speeds' 
according to the field.

According to the existing implementations of all drivers, it seems that 
both of the above behaviors exist.

How should we report and use it?


Thanks

Lijun Ou

Re: [dpdk-dev] [RFC] some questions for speed_capa usage

[Ferruh Yigit]

On 1/18/2021 10:27 AM, oulijun wrote:
> Hi,
> 
> 
> The 'speed_capa' will be reported in rte_eth_dev_info_get API. How should users 
> use the field?
> 
> 1) The driver reports only the capabilities supported by the NIC, and users only 
> obtain the capabilities.
> Maybe, there is a case that a rate bit in 'speed_capa' is not supported by the 
> current transmission medium,
> such as, copper cable optical modules and optical interface modules.
> 
> 2) The field is used only to inform users of the speed_capa supported by the 
> current transmission medium.
> And users set the fixed speed or auto-negotiation by using 'link_speeds' 
> according to the field.
> 
> According to the existing implementations of all drivers, it seems that both of 
> the above behaviors exist.
> 
> How should we report and use it?
> 

Hi Lijun,

When the driver reports the capabilities supported by the NIC, we tend to mark 
this feature as partially supported.

The expectation is the driver report the capability for the current 
configuration, the PHY/FW/transmission medium, whatever it is.

Driver should return the current supported values so that application can select 
one, as you said.

Regards,
ferruh

Re: [dpdk-dev] [RFC] some questions for speed_capa usage

[oulijun]

在 2021/1/18 19:23, Ferruh Yigit 写道:
> On 1/18/2021 10:27 AM, oulijun wrote:
>> Hi,
>>
>>
>> The 'speed_capa' will be reported in rte_eth_dev_info_get API. How 
>> should users use the field?
>>
>> 1) The driver reports only the capabilities supported by the NIC, and 
>> users only obtain the capabilities.
>> Maybe, there is a case that a rate bit in 'speed_capa' is not 
>> supported by the current transmission medium,
>> such as, copper cable optical modules and optical interface modules.
>>
>> 2) The field is used only to inform users of the speed_capa supported 
>> by the current transmission medium.
>> And users set the fixed speed or auto-negotiation by using 
>> 'link_speeds' according to the field.
>>
>> According to the existing implementations of all drivers, it seems 
>> that both of the above behaviors exist.
>>
>> How should we report and use it?
>>
> 
> Hi Lijun,
> 
> When the driver reports the capabilities supported by the NIC, we tend 
> to mark this feature as partially supported.
> 
> The expectation is the driver report the capability for the current 
> configuration, the PHY/FW/transmission medium, whatever it is.
> 
> Driver should return the current supported values so that application 
> can select one, as you said.
> 
Thank you for your answer. I see.
> Regards,
> ferruh
> .
>