Re: [PATCH 20/31] drm/i915: simplify the reduced clock handling for pch plls

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jun 13, 2013 at 01:32:03PM +0100, Damien Lespiau wrote:
> On Thu, Jun 13, 2013 at 01:35:44PM +0200, Daniel Vetter wrote:
> > On Thu, Jun 13, 2013 at 1:26 PM, Damien Lespiau
> > <damien.lespiau@intel.com> wrote:
> > > On Wed, Jun 05, 2013 at 01:34:22PM +0200, Daniel Vetter wrote:
> > >> Just move the lowfreq_avail logic out of the register writing as a
> > >> prep step for the next patch, which will coalesce all the pch pll
> > >> enabling into one spot.
> > >>
> > >> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > >> ---
> > >>  drivers/gpu/drm/i915/intel_display.c | 11 ++++++-----
> > >>  1 file changed, 6 insertions(+), 5 deletions(-)
> > >>
> > >> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > >> index ecf0b1e..fc1b5f7 100644
> > >> --- a/drivers/gpu/drm/i915/intel_display.c
> > >> +++ b/drivers/gpu/drm/i915/intel_display.c
> > >> @@ -5686,7 +5686,10 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
> > >>               if (encoder->pre_pll_enable)
> > >>                       encoder->pre_pll_enable(encoder);
> > >>
> > >> -     intel_crtc->lowfreq_avail = false;
> > >> +     if (is_lvds && has_reduced_clock && i915_powersave)
> > >> +             intel_crtc->lowfreq_avail = true;
> > >
> > > is_lvds doesn't seem necessary as ironlake_compute_clocks() won't set
> > > has_reduced_clock to true if !is_lvds. Doesn't hurt either.
> > 
> > I want to move this all into encoder compute_config callbacks anyway,
> > so that we can neatly subsume eDP DRRS support, too. Until that's
> > fixed I don't care about a bit of fluff ...
> > 
> > >> +     else
> > >> +             intel_crtc->lowfreq_avail = false;
> > >>
> > >>       if (intel_crtc->config.has_pch_encoder) {
> > >>               pll = intel_crtc_to_shared_dpll(intel_crtc);
> > >> @@ -5704,12 +5707,10 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
> > >>                */
> > >>               I915_WRITE(PCH_DPLL(pll->id), dpll);
> > >>
> > >> -             if (is_lvds && has_reduced_clock && i915_powersave) {
> > >> +             if (has_reduced_clock)
> > >>                       I915_WRITE(PCH_FP1(pll->id), fp2);
> > >
> > > Hum this is not quite the same condition? i915_powersave could be false
> > > and we don't want to take that branch? maybe reuse lowfreq_avail?
> > >
> > > Maybe compute_clocks() could check i915_powersave itself and set
> > > has_reduced_clock (or use_reduced_clock) correctly.
> > 
> > Well the entire lowfreq stuff is ripe for overhaul anyway, my plan is
> > to move it all into the pipe config.
> > 
> > For this case here of writing the FP1 register it doesn't matter if we
> > uncodntionally do it, since FP1 doesn't have any effect if we don't
> > enable the lowfreq mode. Which despite the appearance we currently
> > don't do at all on ilk+ ;-)
> > 
> > I should have mentioned this in the comment message. r-b if I fix that
> > while applying?
> 
> yes!

Added ...

> Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>

... and queued for -next, thanks for the review.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch