Re: [PATCH v5 14/18] PCI/pwrctl: add a power control driver for WCN7850

Konrad Dybcio
2024-02-20T21:21:11Z

On 20.02.2024 13:47, Mark Brown wrote:
> On Tue, Feb 20, 2024 at 12:22:42PM +0100, Bartosz Golaszewski wrote:
>> On Mon, Feb 19, 2024 at 6:50 PM Mark Brown <broonie@kernel.org> wrote:
>>> On Fri, Feb 16, 2024 at 09:32:11PM +0100, Bartosz Golaszewski wrote:
>
>>>> +static struct pci_pwrctl_wcn7850_vreg pci_pwrctl_wcn7850_vregs[] = {
>>>> + {
>>>> + .name = "vdd",
>>>> + .load_uA = 16000,
>>>> + },
>
>>> I know a bunch of the QC stuff includes these load numbers but are they
>>> actually doing anything constructive? It keeps coming up that they're
>>> causing a bunch of work and it's not clear that they have any great
>>> effect on modern systems.
>
>> Yes, we have what is called a high-power mode and a low-power mode in
>> regulators and these values are used to determine which one to use.
>
> Are you *sure* this actually happens (and that the regulators don't
> figure it out by themselves), especially given that the consumers are
> just specifying the load once rather than varying it dynamically at
> runtime which is supposed to be the use case for this API? This API is
> intended to be used dynamically, if the regulator always needs to be in
> a particular mode just configure that statically.

*AFAIU*

The regulators aggregate the requested current (there may be
multiple consumers) and then it's decided if it's high enough
to jump into HPM.

Konrad