Re: [Intel-gfx] [PATCH 0/3] Add _PICK_EVEN_RANGES

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 11 Oct 2022, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> Add a new macro, _PICK_EVEN_RANGES, that supports using 2 address
> ranges. This should cover most of our needs for _MMIO_PLL3 and such.
> To show what is achieved with the new macro, convert some PLL-related
> macros to use it instead of _MMIO_PLL3.

While there's nothing particularly wrong about the solution when looked
at in isolation, I do have pretty strong reservations on the whole.

We have:

1) _PICK_EVEN() used in _PIPE() and friends

2) _PICK() used in _MMIO_PIPE3() and friends

3) ->pipe_offsets[] etc. adjustment used in _MMIO_PIPE2() and friends

4) ->ddi_index[] mapping proposed in [1]

5) _PICK_EVEN_RANGES() proposed here

Originally we only had the first one, when the hardware was
simpler. Every single addition since then made sense at the time, but if
we add 4 & 5 to the mix, I think it's just too many options.

I think it's time to take a step back and figure out if there's a more
generic approach that could be used.


BR,
Jani.


[1] https://patchwork.freedesktop.org/series/108833/

-- 
Jani Nikula, Intel Open Source Graphics Center