On 1/8/2020 1:58 PM, Laurent Hardy wrote: > > On 1/8/20 2:06 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. >> >> >>> 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. >> >> >>> 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. > > I can provide a V2 which will remove the useless dev_led_ctrl_capable ops.
+1, dev_led_ctrl_capable is not used. > > About the 'is_supported()' versions of APIs, in the current patch I > factorize > the check on dev ops on and off availability in a same function named > "led_ctrl_capable" but I can rename it if required. > > Just in this specific case I don't dissociate on and off capability, as > being > able to set the led off without a way to set it on again sounds a bit > unusual :) What about following, Right now there is not way to get led status, only have on/off We can store status in ethdev layer add a 'rte_eth_led_status' which can return status. If the on/off dev_ops are not set, it can return 'unavailable' which covers your usecase.
