Hi Adam,

Just sent out a patch stack https://patchwork.kernel.org/project/linux-usb/list/?series=461087 to address the issue that you mentioned here.

Thanks, Badhri

On Mon, Apr 5, 2021 at 6:43 PM Badhri Jagan Sridharan badhri@google.com wrote:

Hi Adam,

Just sent out a patch stack https://patchwork.kernel.org/project/linux-usb/list/?series=461087 to address the issue that you mentioned here.

Thanks, Badhri

On Fri, Mar 19, 2021 at 9:32 AM Adam Thomson Adam.Thomson.Opensource@diasemi.com wrote:

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On 18 March 2021 20:40, Badhri Jagan Sridharan wrote:

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Regarding selecting PDOs or PPS APDOs, surely we should only notify of a

change

...

when we reach SNK_READY which means a new contract has been established?

Until

...

that point it's possible any requested change could be rejected so why inform clients before we know the settings have taken effect? I could be missing something here as it's been a little while since I delved into this, but this doesn't seem to make sense to me.

I was trying to keep the power_supply_changed call close to the variables which are used to infer the power supply property values. Since port->pps_data.max_curr is already updated here and that's used to infer the CURRENT_MAX a client could still read this before the request goes through right ?

Actually that's fair but I think the problem here relates to 'max_curr' not being reset if the SRC rejects our request when we're swapping between one PPS APDO and another PPS APDO. I think the 'max_curr' value should be reverted back to the value for the existing PPS APDO we were already using. I suspect the same might be true of 'min_volt' and 'max_volt' as well, now I look at it. It might actually be prudent to have pending PPS data based on a request, which is only committed as active once ACCEPT has been received.

Regarding power_supply_changed() though, I still think we should only notify of a change when the requested change has been accepted by the source, in relation to these values as they should reflect the real, in-use voltage and current values.