[Intel-gfx] [PATCH] drm/i915: Rename global latency_ns variable

Daniel Vetter daniel at ffwll.ch
Wed Sep 3 15:12:10 CEST 2014


On Wed, Sep 03, 2014 at 02:17:52PM +0300, Ville Syrjälä wrote:
> On Wed, Sep 03, 2014 at 11:56:07AM +0100, Chris Wilson wrote:
> > We use the variable name latency_ns in both the local lowlevel wm
> > calculation routines and at the global level. Rename the global value to
> > reduce shadow warnings and future confusion.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> This has confused me occasioanlly in the past. Though I'm not sure if
> it would be better to move it into local scope instead since we already
> have the sr_lantency_ns in there for some platforms. Also I'm not sure
> 5us is really a good value.

I've had some patches to clean up the gmch wm calculation code since
there's a few other really confusing things in there. But it's also a lot
of tricky/fragile code :(

> But anyway we can massage it further if anyone cares enough. In the
> meantime this makes things clearer at least, so:
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Queued for -next, thanks for the patch.
-Daniel
> 
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c | 36 ++++++++++++++++++------------------
> >  1 file changed, 18 insertions(+), 18 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index a2340e87dd20..425d5e4052ae 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -872,7 +872,7 @@ void intel_set_memory_cxsr(struct drm_i915_private *dev_priv, bool enable)
> >   * A value of 5us seems to be a good balance; safe for very low end
> >   * platforms but not overly aggressive on lower latency configs.
> >   */
> > -static const int latency_ns = 5000;
> > +static const int pessimal_latency_ns = 5000;
> >  
> >  static int i9xx_get_fifo_size(struct drm_device *dev, int plane)
> >  {
> > @@ -1387,14 +1387,14 @@ static void valleyview_update_wm(struct drm_crtc *crtc)
> >  	vlv_update_drain_latency(crtc);
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_A,
> > -			    &valleyview_wm_info, latency_ns,
> > -			    &valleyview_cursor_wm_info, latency_ns,
> > +			    &valleyview_wm_info, pessimal_latency_ns,
> > +			    &valleyview_cursor_wm_info, pessimal_latency_ns,
> >  			    &planea_wm, &cursora_wm))
> >  		enabled |= 1 << PIPE_A;
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_B,
> > -			    &valleyview_wm_info, latency_ns,
> > -			    &valleyview_cursor_wm_info, latency_ns,
> > +			    &valleyview_wm_info, pessimal_latency_ns,
> > +			    &valleyview_cursor_wm_info, pessimal_latency_ns,
> >  			    &planeb_wm, &cursorb_wm))
> >  		enabled |= 1 << PIPE_B;
> >  
> > @@ -1453,20 +1453,20 @@ static void cherryview_update_wm(struct drm_crtc *crtc)
> >  	vlv_update_drain_latency(crtc);
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_A,
> > -			    &valleyview_wm_info, latency_ns,
> > -			    &valleyview_cursor_wm_info, latency_ns,
> > +			    &valleyview_wm_info, pessimal_latency_ns,
> > +			    &valleyview_cursor_wm_info, pessimal_latency_ns,
> >  			    &planea_wm, &cursora_wm))
> >  		enabled |= 1 << PIPE_A;
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_B,
> > -			    &valleyview_wm_info, latency_ns,
> > -			    &valleyview_cursor_wm_info, latency_ns,
> > +			    &valleyview_wm_info, pessimal_latency_ns,
> > +			    &valleyview_cursor_wm_info, pessimal_latency_ns,
> >  			    &planeb_wm, &cursorb_wm))
> >  		enabled |= 1 << PIPE_B;
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_C,
> > -			    &valleyview_wm_info, latency_ns,
> > -			    &valleyview_cursor_wm_info, latency_ns,
> > +			    &valleyview_wm_info, pessimal_latency_ns,
> > +			    &valleyview_cursor_wm_info, pessimal_latency_ns,
> >  			    &planec_wm, &cursorc_wm))
> >  		enabled |= 1 << PIPE_C;
> >  
> > @@ -1559,14 +1559,14 @@ static void g4x_update_wm(struct drm_crtc *crtc)
> >  	bool cxsr_enabled;
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_A,
> > -			    &g4x_wm_info, latency_ns,
> > -			    &g4x_cursor_wm_info, latency_ns,
> > +			    &g4x_wm_info, pessimal_latency_ns,
> > +			    &g4x_cursor_wm_info, pessimal_latency_ns,
> >  			    &planea_wm, &cursora_wm))
> >  		enabled |= 1 << PIPE_A;
> >  
> >  	if (g4x_compute_wm0(dev, PIPE_B,
> > -			    &g4x_wm_info, latency_ns,
> > -			    &g4x_cursor_wm_info, latency_ns,
> > +			    &g4x_wm_info, pessimal_latency_ns,
> > +			    &g4x_cursor_wm_info, pessimal_latency_ns,
> >  			    &planeb_wm, &cursorb_wm))
> >  		enabled |= 1 << PIPE_B;
> >  
> > @@ -1709,7 +1709,7 @@ static void i9xx_update_wm(struct drm_crtc *unused_crtc)
> >  		adjusted_mode = &to_intel_crtc(crtc)->config.adjusted_mode;
> >  		planea_wm = intel_calculate_wm(adjusted_mode->crtc_clock,
> >  					       wm_info, fifo_size, cpp,
> > -					       latency_ns);
> > +					       pessimal_latency_ns);
> >  		enabled = crtc;
> >  	} else {
> >  		planea_wm = fifo_size - wm_info->guard_size;
> > @@ -1731,7 +1731,7 @@ static void i9xx_update_wm(struct drm_crtc *unused_crtc)
> >  		adjusted_mode = &to_intel_crtc(crtc)->config.adjusted_mode;
> >  		planeb_wm = intel_calculate_wm(adjusted_mode->crtc_clock,
> >  					       wm_info, fifo_size, cpp,
> > -					       latency_ns);
> > +					       pessimal_latency_ns);
> >  		if (enabled == NULL)
> >  			enabled = crtc;
> >  		else
> > @@ -1827,7 +1827,7 @@ static void i845_update_wm(struct drm_crtc *unused_crtc)
> >  	planea_wm = intel_calculate_wm(adjusted_mode->crtc_clock,
> >  				       &i845_wm_info,
> >  				       dev_priv->display.get_fifo_size(dev, 0),
> > -				       4, latency_ns);
> > +				       4, pessimal_latency_ns);
> >  	fwater_lo = I915_READ(FW_BLC) & ~0xfff;
> >  	fwater_lo |= (3<<8) | planea_wm;
> >  
> > -- 
> > 2.1.0
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch



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