Re: [PATCH v2 00/48] Introduce core voltage scaling for NVIDIA Tegra20/30 SoCs
From: Krzysztof Kozlowski
Date: Tue Jan 05 2021 - 12:11:59 EST
On Thu, Dec 17, 2020 at 09:05:50PM +0300, Dmitry Osipenko wrote:
> Introduce core voltage scaling for NVIDIA Tegra20/30 SoCs, which reduces
> power consumption and heating of the Tegra chips. Tegra SoC has multiple
> hardware units which belong to a core power domain of the SoC and share
> the core voltage. The voltage must be selected in accordance to a minimum
> requirement of every core hardware unit.
> The minimum core voltage requirement depends on:
> 1. Clock enable state of a hardware unit.
> 2. Clock frequency.
> 3. Unit's internal idling/active state.
> This series is tested on Acer A500 (T20), AC100 (T20), Nexus 7 (T30),
> Ouya (T30), TK1 (T124) and some others. I also added voltage scaling to
> the Ventana (T20) and Cardhu (T30) boards which are tested by NVIDIA's CI
> farm. Tegra30 is now couple degrees cooler on Nexus 7 and stays cool on
> Ouya (instead of becoming burning hot) while system is idling. It should
> be possible to improve this further by implementing a more advanced power
> management features for the kernel drivers.
> The DVFS support is opt-in for all boards, meaning that older DTBs will
> continue to work like they did it before this series. It should be possible
> to easily add the core voltage scaling support for Tegra114+ SoCs based on
> this grounding work later on, if anyone will want to implement it.
The same comment as for your interconnect work: for sets touching
multiple systems please mention the dependencies between patches in the
cover letter. Not as a reply to such remark like I make here, but as a
separate entry in the cover letter.