Re: [PATCH v3 2/2] media: atomisp: remove redundant call to ia_css_output0_configure()

["Jose A. Perez de Azpillaga" <azpijr@gmail.com>]

On Fri, Apr 03, 2026 at 08:42:11AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Apr 02, 2026 at 08:33:45PM +0200, Jose A. Perez de Azpillaga wrote:
> > The function configure_isp_from_args() contained a duplicate call to
> > ia_css_output0_configure() using the same output frame index. Remove the
> > redundant call to simplify the configuration path.
>
> Are you sure the hardware doesn't actually need this called twice?  Lots
> of devices need to be told multiple times what to do in order for it to
> "stick", hardware is "fun" that way :(
>

The concern is valid in general, but ia_css_output0_configure() does not
write to a hardware register.

ia_css_configure_output0() writes into binary->mem_params.params[], a
software-side DMEM parameter buffer in kernel memory. the ISP firmware
receives these parameters later as a batch, not at the time of the call.
calling a pure memory write twice with the same pointer and same value
simply overwrites the same location with identical data, there is no
hardware interaction that could require repetition.

> Have you tested this?
>

as noted in the cover letter, I don't have the hardware to test this.

--
regards,
jose a. p-a