Re: [PATCH] [RFC PATCH] staging: media: atomisp: remove redundant ov2722_startup() helper

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

On Sun, 9 Aug 2026 20:17:15 +0200
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Sun, Aug 09, 2026 at 11:31:05PM +0530, Mohit Mishra wrote:
> > In atomisp-ov2722.c, ov2722_startup() was invoked inside
> > ov2722_set_fmt() to program sensor hardware registers during format
> > negotiation, accompanied by a "TODO: remove it" comment.
> > 
> > Standard V4L2 subdevice drivers do not program hardware registers during
> > .set_fmt(), but defer hardware register configuration to stream start
> > (.s_stream(1)).
> > 
> > This patch:
> > 1. Removes the ov2722_startup() helper function and its TODO comment.
> > 2. Refactors register initialization into a static
> >    ov2722_startup_registers() helper.
> > 3. Moves sensor software reset and resolution register array configuration
> >    into ov2722_s_stream() when enable == 1.
> > 4. Preserves the PMIC power-cycle retry loop on startup failure inside
> >    ov2722_s_stream(1) to maintain hardware fault-tolerance for AtomISP
> >    tablets.
> > 5. Updates ov2722_set_fmt() to purely update internal software state.
> > 
> > BEHAVIORAL RISK & UNTESTED NOTICE:
> > This is a functional timing change. Deferring hardware register writes to
> > .s_stream(1) has not been tested on physical Intel AtomISP hardware.
> > Submitted as RFC for review by AtomISP maintainers (Hans de Goede,
> > Mauro Carvalho Chehab).  
> 
> I would recommend doing changes like this ONLY if you have the hardware
> to test it with.

Agreed. You should also run v4l2-compliance tools to check if the
V4L2 API behavior didn't cause regressions.

> 
> And did you forget an Assisted-by: tag?
> 
> thanks,
> 
> greg k-h



Thanks,
Mauro