[Intel-gfx] [PATCH] drm/i915: save state of AUD_FREQ_CNTRL on all gen9+ platforms

[Kai Vehmanen]

Hey,

On Tue, 31 Dec 2019, Matt Roper wrote:

> On Tue, Dec 31, 2019 at 04:47:18PM +0200, Kai Vehmanen wrote:
> > On old platforms the default values of AUD_FREQ_CNTRL are
> > typically used (as set by BIOS), so this has not been an issue,
> > but future platforms will definitely need this. Extend the state
> > save logic to cover all gen9+ platforms.
[...]
> Given that the lack of this save/restore was causing noticeable problems
> on ICL/TGL, do you know whether the same problems were also seen on
> EHL/JSL?  If so, we may want Cc: stable and Fixes: tags so that it gets
> backported?

the fix is most critical for TGL and later (due to changed hw default 
values gen12 display onwards). For EHL/JSL, this would seem less important 
as systems are shipping using the hw default configuration in which case 
this patch is not needed. Based on current data, I'd probably skip the Cc 
stable at this point as TGL is already covered -- or limit to "v5.5+". 

PS A newbie question, if decision is to cc stable, should I add it as the 
   original submitted and resend V2, or are stable tags typically
   added by the intel-gfx maintainers when applying a patch (i.e. no 
   actions needed from me). In sound tree, latter seems to be the norm..
   I see both conventions used here on intel-gfx.

Br, Kai