Re: [PATCH v7 0/3] hwrng: add hwrng support for Rockchip RK3568

[Heiko Stübner]

Am Dienstag, 30. Juli 2024, 11:03:06 CEST schrieb Diederik de Haas:
> On Tuesday, 30 July 2024 01:18:37 CEST Daniel Golle wrote:
> > On Wed, Jul 24, 2024 at 08:07:51AM +0200, Dragan Simic wrote:
> > > Thanks a lot for the testing.  Though, such wildly different test results
> > > can, regrettably, lead to only one conclusion:  the HWRNG found in RK3566
> > > is unusable. :/
> 
> FTR: I agree with Dragan, unfortunately.
> 
> > The results on RK3568 look much better and the series right now also
> > only enabled the RNG on RK3568 systems. However, we have only seen few
> > boards with RK3568 up to now, and I only got a couple of NanoPi R5C
> > here to test, all with good hwrng results.
> > 
> > Do you think it would be agreeable to only enable the HWRNG for RK3568
> > as suggested in this series? Or are we expecting quality to also vary
> > as much as it (sadly) does for RK3566?
> 
> Unless we get *evidence* to the contrary, we should assume that the HWRNG on 
> RK3568 is fine as the currently available test results are fine.
> So I think enabling it only for RK3568 is the right thing to do.
> 
> So a 'revert' to v7 variant seems appropriate, but with the following changes:
> - Add `status = "disabled";` property to the definition in rk356x.dtsi
> - Add a new commit where you enable it only for rk3568 and document in the 
> commit message why it's not enabled on rk3566 with a possible link to the v7 
> thread for clarification on why that is

I was going to protest about the "disable" until reading the 2nd part :-D .

And yeah that makes a lot of sense, "add" it to rk356x.dtsi, as the IP is
part of both variants, but only enable it in rk3568.dtsi because of the
seemingly faulty implementation on the rk3566.


> You could probably also integrate that into 1 commit, but make sure that the 
> commit summary and description match the implementation.
> IMO that wasn't 'technically' the case in v8 as the rng node was added to 
> rk356x, but it was only enabled on rk3568.
> 
> My 0.02