[Intel-gfx] [PATCH] drm/i915/display: Add a debugfs entry for fifo underruns

[Andi Shyti]

Hi Swati,

[...]

> +static void intel_fifo_underrun_inc_count(struct intel_crtc *crtc,
> +					  bool is_cpu_fifo)

I'm not a big fan of the true/false parameters in functions. I
actually hate them because it's never clear from the caller what
the true/false means.

Isn't it clear to just have some wrappers

#define intel_fifo_underrun_inc_cpu_count(...)
#define intel_fifo_underrun_inc_cph_count(...)

or similar?

> +{
> +#ifdef CONFIG_DEBUG_FS
> +	if (is_cpu_fifo)
> +		crtc->cpu_fifo_underrun_count++;
> +	else
> +		crtc->pch_fifo_underrun_count++;
> +#endif
> +}
> +
>  static void i9xx_check_fifo_underruns(struct intel_crtc *crtc)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> @@ -103,6 +114,7 @@ static void i9xx_check_fifo_underruns(struct intel_crtc *crtc)
>  	intel_de_write(dev_priv, reg, enable_mask | PIPE_FIFO_UNDERRUN_STATUS);
>  	intel_de_posting_read(dev_priv, reg);
>  
> +	intel_fifo_underrun_inc_count(crtc, true);
>  	trace_intel_cpu_fifo_underrun(dev_priv, crtc->pipe);
>  	drm_err(&dev_priv->drm, "pipe %c underrun\n", pipe_name(crtc->pipe));
>  }
> @@ -156,6 +168,7 @@ static void ivb_check_fifo_underruns(struct intel_crtc *crtc)
>  	intel_de_write(dev_priv, GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));
>  	intel_de_posting_read(dev_priv, GEN7_ERR_INT);
>  
> +	intel_fifo_underrun_inc_count(crtc, true);
>  	trace_intel_cpu_fifo_underrun(dev_priv, pipe);
>  	drm_err(&dev_priv->drm, "fifo underrun on pipe %c\n", pipe_name(pipe));
>  }
> @@ -244,6 +257,7 @@ static void cpt_check_pch_fifo_underruns(struct intel_crtc *crtc)
>  		       SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
>  	intel_de_posting_read(dev_priv, SERR_INT);
>  
> +	intel_fifo_underrun_inc_count(crtc, false);
>  	trace_intel_pch_fifo_underrun(dev_priv, pch_transcoder);
>  	drm_err(&dev_priv->drm, "pch fifo underrun on pch transcoder %c\n",
>  		pipe_name(pch_transcoder));
> @@ -286,6 +300,11 @@ static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
>  
>  	old = !crtc->cpu_fifo_underrun_disabled;
>  	crtc->cpu_fifo_underrun_disabled = !enable;
> +#ifdef CONFIG_DEBUG_FS
> +	/* don't reset count in fifo underrun irq path */
> +	if (!in_irq() && !enable)
> +		crtc->cpu_fifo_underrun_count = 0;
> +#endif
>  
>  	if (HAS_GMCH(dev_priv))
>  		i9xx_set_fifo_underrun_reporting(dev, pipe, enable, old);
> @@ -365,6 +384,11 @@ bool intel_set_pch_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
>  
>  	old = !crtc->pch_fifo_underrun_disabled;
>  	crtc->pch_fifo_underrun_disabled = !enable;
> +#ifdef CONFIG_DEBUG_FS
> +	/* don't reset count in fifo underrun irq path */
> +	if (!in_irq() && !enable)
> +		crtc->pch_fifo_underrun_count = 0;
> +#endif

All these ifdefs are a bit ugly. Can we put all these stuff
inside the debugfs.c file that is compiled only if DEBUG_FS is
configured?

Andi

>  
>  	if (HAS_PCH_IBX(dev_priv))
>  		ibx_set_fifo_underrun_reporting(&dev_priv->drm,
> @@ -434,6 +458,7 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
>  			drm_err(&dev_priv->drm, "CPU pipe %c FIFO underrun\n", pipe_name(pipe));
>  	}
>  
> +	intel_fifo_underrun_inc_count(crtc, true);
>  	intel_fbc_handle_fifo_underrun_irq(dev_priv);
>  }