Re: [Intel-gfx] [PATCH 0/6] Introduce struct cdclk_step

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Sep 23, 2022 at 04:56:53PM +0000, Srivatsa, Anusha wrote:
> 
> 
> > -----Original Message-----
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Sent: Tuesday, September 20, 2022 2:59 PM
> > To: Srivatsa, Anusha <anusha.srivatsa@intel.com>
> > Cc: intel-gfx@lists.freedesktop.org; Shankar, Uma
> > <uma.shankar@intel.com>; Vivi, Rodrigo <rodrigo.vivi@intel.com>
> > Subject: Re: [PATCH 0/6] Introduce struct cdclk_step
> > 
> > On Tue, Sep 20, 2022 at 06:48:46PM +0000, Srivatsa, Anusha wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > Sent: Tuesday, September 20, 2022 1:20 AM
> > > > To: Srivatsa, Anusha <anusha.srivatsa@intel.com>
> > > > Cc: intel-gfx@lists.freedesktop.org; Shankar, Uma
> > > > <uma.shankar@intel.com>; Vivi, Rodrigo <rodrigo.vivi@intel.com>
> > > > Subject: Re: [PATCH 0/6] Introduce struct cdclk_step
> > > >
> > > > On Fri, Sep 16, 2022 at 05:43:58PM -0700, Anusha Srivatsa wrote:
> > > > > This is a prep series for the actual cdclk refactoring that will
> > > > > be sent following this. Idea is to have a struct - cdclk_step that
> > > > > holds the following:
> > > > > - cdclk action (squash, crawl or modeset)
> > > > > - cdclk frequency
> > > > > which gets populated in atomic check. Driver uses the populated
> > > > > values during atomic commit to do the suitable sequence of actions
> > > > > like programming squash ctl registers in case of squashing or PLL
> > > > > sequence incase of modeset and so on.
> > > > >
> > > > > This series just addresses the initial idea. The actual plumming
> > > > > in the atomic commit phase will be sent shortly.
> > > >
> > > > OK, people keep ignoring what I say so I just typed up the code
> > > > quickly. This to me seems like the most straightforward way to do what
> > we need:
> > > > https://github.com/vsyrjala/linux.git cdclk_crawl_and_squash
> > > >
> > > > Totally untested ofc, apart from me doing a quick scan through our
> > > > cdclk tables for the crawl+squahs platforms to make sure that this
> > > > approach should produce sane values.
> > > Ville,
> > > Why have a mid cdclk_config? Cant we use the new-cdclk-config for this
> > purpose?
> > 
> > You either
> > - start at old, crawl to mid, then squash to new
> > - start at old, squash to mid, then crawl to new
> 
> Tested the changes on TGL(legacy) and DG2(squash). Took some time to understand the code but the mid cdclk config logic works. @Ville Syrjälä does replacing the intel_cdclk_can_squash() and intel_cdclk_can_crawl() with your new cdclk_crawl_and_squash in atomic check make sense?

I don't think we should need any real logic at that point.
If we can squash and crawl then I think we can always do
the cdclk change w/o a modeset, at least with what we
currently have defined in the cdclk tables.

-- 
Ville Syrjälä
Intel