[Intel-gfx] [PATCH] drm/i915/bdw: Simple IPS pixel_rate x 0.95 cdclk restriction

[Vivi, Rodrigo]

On Wed, 2015-05-20 at 20:26 +0300, Ville Syrjälä wrote:
> On Wed, May 20, 2015 at 09:42:57AM -0700, Rodrigo Vivi wrote:
> > Broadwell Workaround : Do not enable IPS when the pipe pixel rate is
> > greater than
> > 95% of the CDCLK frequency.  The pipe pixel rate is the port pixel rate
> > multiplied by the pipe scaler down scale amount.
> 
> Or just merge my patch doing the same thing?

I was trying to make the simple possible since latest one that I was
looking at was depending on a series of many patches. It was caching the
max cdclk, etc... 

But now I looked again your first one and saw the history there that got
merged but it was removed due to unclaimed registers...

Now I see that my patch and your original one aren't so different... I'm
sorry...

So I was telling Paulo that with my patch I can't get Unclaimed messages
anymore and when double cheking I noticed that runing pm_rpm rte with no
patch I get the "Unclaimed register detected before reading register
0x130040"

So I believe your first patch is good to get merged. I believe that
"Unclaimed reg" that Paulo saw was something else.

So, back to yours...

> 
> > 
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 9 +++++++++
> >  drivers/gpu/drm/i915/intel_drv.h     | 2 ++
> >  drivers/gpu/drm/i915/intel_pm.c      | 4 ++--
> >  3 files changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 9d2d6fb..dd8ef51 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -112,6 +112,7 @@ static int i9xx_get_refclk(const struct intel_crtc_state *crtc_state,
> >  			   int num_connectors);
> >  static void intel_crtc_enable_planes(struct drm_crtc *crtc);
> >  static void intel_crtc_disable_planes(struct drm_crtc *crtc);
> > +static int broadwell_get_display_clock_speed(struct drm_device *dev);
> >  
> >  static struct intel_encoder *intel_find_encoder(struct intel_connector *connector, int pipe)
> >  {
> > @@ -4948,6 +4949,14 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
> >  /* IPS only exists on ULT machines and is tied to pipe A. */
> >  static bool hsw_crtc_supports_ips(struct intel_crtc *crtc)
> >  {
> > +	struct drm_device *dev = crtc->base.dev;
> > +
> > +	if (IS_BROADWELL(dev) && ilk_pipe_pixel_rate(dev, &crtc->base) >
> > +	    broadwell_get_display_clock_speed(dev) * 95/100) {
> > +		DRM_DEBUG_KMS("IPS avoided because pixel rate is greater than 95 percent of CDCLK\n");
> > +		return false;
> > +	}
> > +
> >  	return HAS_IPS(crtc->base.dev) && crtc->pipe == PIPE_A;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 47bc729..c59fa3f 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1341,6 +1341,8 @@ void intel_display_set_init_power(struct drm_i915_private *dev, bool enable);
> >  /* intel_pm.c */
> >  void intel_init_clock_gating(struct drm_device *dev);
> >  void intel_suspend_hw(struct drm_device *dev);
> > +uint32_t ilk_pipe_pixel_rate(struct drm_device *dev,
> > +			     struct drm_crtc *crtc);
> >  int ilk_wm_max_level(const struct drm_device *dev);
> >  void intel_update_watermarks(struct drm_crtc *crtc);
> >  void intel_update_sprite_watermarks(struct drm_plane *plane,
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index ce1d079..0afeae8 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -1434,8 +1434,8 @@ static void i845_update_wm(struct drm_crtc *unused_crtc)
> >  	I915_WRITE(FW_BLC, fwater_lo);
> >  }
> >  
> > -static uint32_t ilk_pipe_pixel_rate(struct drm_device *dev,
> > -				    struct drm_crtc *crtc)
> > +uint32_t ilk_pipe_pixel_rate(struct drm_device *dev,
> > +			     struct drm_crtc *crtc)
> >  {
> >  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> >  	uint32_t pixel_rate;
> > -- 
> > 2.1.0
> > 
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