[Intel-gfx] [PATCH 1/3] drm/i915: Add struct to hold IP version

[Jani Nikula]

On Tue, 19 Oct 2021, José Roberto de Souza <jose.souza at intel.com> wrote:
> The constant platform display version is not using this new struct but
> the runtime variant will definitely use it.

Cc: Some more folks to hijack this thread. Sorry! ;)

We added runtime info to i915, because we had this idea and goal of
turning the device info to a truly const pointer to the info structures
in i915_pci.c that are stored in rodata. The idea was that we'll have a
complete split of mutable and immutable device data, with all the
mutable data in runtime info.

Alas, we never got there. More and more data that was mostly const but
sometimes needed tweaking kept piling up. mkwrite_device_info() was
supposed to be a clue not to modify device info runtime, but instead it
proliferated. Now we have places like intel_fbc_init() disabling FBC
through that. But most importantly, we have fusing that considerably
changes the device info, and the copying all of that data over to
runtime info probably isn't worth it.

Should we just acknowledge that the runtime info is useless, and move
some of that data to intel_device_info and some of it elsewhere in i915?


BR,
Jani.

-- 
Jani Nikula, Intel Open Source Graphics Center