On 1/8/2020 1:06 PM, Thomas Monjalon wrote: > 08/01/2020 13:59, Ferruh Yigit: >> On 1/8/2020 10:31 AM, Laurent Hardy wrote: >>> Hi all, >>> >>> On 1/8/20 10:55 AM, David Marchand wrote: >>>> On Wed, Jan 8, 2020 at 10:09 AM Ferruh Yigit <ferruh.yi...@intel.com> >>>> wrote: >>>>> On 1/8/2020 8:56 AM, David Marchand wrote: >>>>>> Hello Laurent, >>>>>> >>>>>> Bonne année. >>>>>> >>>>>> Cc: maintainers. >>>>>> >>>>>> On Tue, Jan 7, 2020 at 3:57 PM Laurent Hardy <laurent.ha...@6wind.com> >>>>>> wrote: >>>>>>> In current led control API we have no way to know if a device is able >>>>>>> to handle on/off requests coming from the application. >>>>>>> Knowing if the device is led control capable could be useful to avoid >>>>>>> exchanges between application and kernel. >>>>>>> Using the on/off requests to flag if the device is led control capable >>>>>>> (based on the ENOSUP returned error) is not convenient as such request >>>>>>> can change the led state on device. >>>>>>> >>>>>>> This patch adds a new function rte_eth_led_ctrl_capable() that will look >>>>>>> for led_off/on dev ops availability on the related pmd, to know if the >>>>>>> device is able to handle such led control requests (on/off). >>>>>> This patch breaks the ABI, which is BAD :-). >>>>> Why it is an ABI break, dev_ops should be between library and drivers, so >>>>> it >>>>> should be out of the ABI concern, isn't it. >>>> You are right. >>>> So in our context, this is not an ABI breakage. >>>> But abidiff still reports it, so maybe some filtering is required to >>>> avoid this false positive. >>>> >>>> Note that if we insert an ops before rx_queue_count, we would have a >>>> real ABI breakage, as this ops is accessed via an inline wrapper by >>>> applications. >>>> >>>> >>>>>> This new api only needs to look at the existing ops, so you can remove >>>>>> the (unused in your patch) dev_led_ctrl_capable ops. >>>>>> >>>>>> OTOH, would it make sense to expose this capability in dev_flags? >>>>>> >>>>> 'rte_eth_led_on()' & 'rte_eth_led_off()' APIs returns '-ENOTSUP' when the >>>>> not >>>>> supported, can that help application to understand? >>>> You might want to know it is supported without changing the state. >>>> Laurent? >>> >>> First, happy new year :) >>> >>> Yes exactly, the purpose of this patch is to query if the device is led >>> control capable or not without changing the led state. >>> >>> About exposing the capability through a dev_flags, means to make some >>> modification in each pmds. It looks more easy in term of pmds >>> maintenance to relying on the rte_eth_led_off()/on() dev ops >>> availability at rte_ethdev level, right ? >>> >> >> 'dev_flag' definition is not clear, right now it holds the combination of >> status >> and capability. And we have 'rte_eth_dev_info' struct, which is again >> combination of device capability and status. > > I agree capabilities in ethdev are a bit of a mess. > I would appreciate someone makes a complete audit of it > so we can discuss how to improve the situation. > > >> Perhaps we should have explicit capabilities and status fields, even in the >> rte_device level which inherited by net/crypto devices etc.. > > No, ethdev capabilities should stay in ethdev.
No strong opinion, I though a standardized way may help other device abstraction layers too. > > >> 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. > > >> Only we should have it without side effect, >> >> 1- adding an additional 'dry-run' parameter can work, but this means breaking >> ABI and updating majority of the ethdev APIs :) >> 2- Adding 'is_supported' versions of the APIs as we need can be an option, >> like >> 'rte_eth_led_on_is_supported()' >> 3- Olivier's suggestion to add a new API to get the led status, so that this >> information can be used select led API which won't cause side affect and let >> us >> learn if it is supported. >> >> Any other alternatives? >> >> I would prefer the 2) in above ones, which is very similar to the original >> patch. > > The other alternatives are in rte_eth_dev_info and dev_flags. > >
