Re: [PATCH v4 0/7] Add SDM670 camera subsystem

[Richard Acayan <mailingradian@gmail.com>]

On Thu, Sep 05, 2024 at 10:09:34PM +0200, Andi Shyti wrote:
> Hi Richard,
> 
> On Tue, Sep 03, 2024 at 10:04:49PM GMT, Richard Acayan wrote:
> > This adds support for the camera subsystem on the Snapdragon 670.
> > 
> > As of next-20240902, camss seems to be a bit broken, but the same series
> > works on stable (although it is much less reliable now that the CCI clock
> > frequency is not being assigned).
> 
> I am not understanding this bit: is this series making it better
> or not? Can you please clarify what is broken, what is less
> reliable and what works?

When applying this camss series and some camera sensor patches on
linux-next, the Pixel 3a seems to hang when camera capture starts.

When applying the same patches on stable, the camera does not cause the
Pixel 3a to hang.

When these device tree properties from the previous series were removed:

			assigned-clocks = <&camcc CAM_CC_CCI_CLK>;
			assigned-clock-rates = <37500000>;

the CCI would sometimes fail to probe with the error:

	[   51.572732] i2c-qcom-cci ac4a000.cci: deferred probe timeout, ignoring dependency
	[   51.572769] i2c-qcom-cci ac4a000.cci: probe with driver i2c-qcom-cci failed with error -110

On further testing, the rate can be set to 19.2 MHz, and there would be
no failure (or rather, it wouldn't happen often enough for me to witness
it).

> Besides, I'm reading that this series has not been tested and it
> makes it difficult for me to take this in, considering that you
> are adding a new support.

Of course. This revision of the series wasn't submitted to rush into
v6.12-rc1. It can wait until everything is resolved.

When device tree maintainers comment "not tested" on the documentation,
it usually means that `make dt_bindings_check DT_SCHEMA_FILES=...` gives
errors or warnings (even though the device tree and driver may work on
the hardware). It's a separate test and one of the things I haven't
scripted into my workflow, although it's still a responsibility.