[Intel-gfx] [PATCH v2 3/4] drm/i915/psr: Control PSR interrupts via debugfs

Pandiyan, Dhinakaran dhinakaran.pandiyan at intel.com
Tue Mar 27 18:33:11 UTC 2018


On Tue, 2018-03-27 at 13:24 +0300, Ville Syrjälä wrote:
> On Mon, Mar 26, 2018 at 06:16:22PM -0700, Dhinakaran Pandiyan wrote:
> > Interrupts other than the one for AUX errors are required only for debug,
> > so unmask them via debugfs when the user requests debug.
> > 
> > User can make such a request with
> > echo 1 > <DEBUG_FS>/dri/0/i915_edp_psr_debug
> > 
> > v2: Unroll loops (Ville)
> >     Avoid resetting error mask bits.
> > 
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_debugfs.c | 36 +++++++++++++++++++++++-
> >  drivers/gpu/drm/i915/i915_drv.h     |  1 +
> >  drivers/gpu/drm/i915/i915_irq.c     | 55 +++++++++++--------------------------
> >  drivers/gpu/drm/i915/intel_drv.h    |  2 ++
> >  drivers/gpu/drm/i915/intel_psr.c    | 54 ++++++++++++++++++++++++++++++++++++
> >  5 files changed, 108 insertions(+), 40 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > index 7816cd53100a..6fd801ef7cbb 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -2690,6 +2690,39 @@ static int i915_edp_psr_status(struct seq_file *m, void *data)
> >  	return 0;
> >  }
> >  
> > +static int
> > +i915_edp_psr_debug_set(void *data, u64 val)
> > +{
> > +	struct drm_i915_private *dev_priv = data;
> > +
> > +	if (!CAN_PSR(dev_priv))
> > +		return -ENODEV;
> > +
> > +	if (val < 0  || val > 1)
> > +		return -EINVAL;
> 
> Can't be < 0.
> 
> > +
> > +	DRM_DEBUG_KMS("%s PSR debug\n", val == 1 ? "Enabling" : "Disabling");
> 
> ==1 seems pointless
> enableddisabled() could be used perhaps.
> 

Will do.

> 
> > +	intel_psr_debug_control(dev_priv, val);
> > +
> > +	return 0;
> > +}
> > +
> > +static int
> > +i915_edp_psr_debug_get(void *data, u64 *val)
> > +{
> > +	struct drm_i915_private *dev_priv = data;
> > +
> > +	if (!CAN_PSR(dev_priv))
> > +		return -ENODEV;
> > +
> > +	*val = READ_ONCE(dev_priv->psr.debug);
> > +	return 0;
> > +}
> > +
> > +DEFINE_SIMPLE_ATTRIBUTE(i915_edp_psr_debug_fops,
> > +			i915_edp_psr_debug_get, i915_edp_psr_debug_set,
> > +			"%llu\n");
> > +
> >  static int i915_sink_crc(struct seq_file *m, void *data)
> >  {
> >  	struct drm_i915_private *dev_priv = node_to_i915(m->private);
> > @@ -4811,7 +4844,8 @@ static const struct i915_debugfs_files {
> >  	{"i915_guc_log_relay", &i915_guc_log_relay_fops},
> >  	{"i915_hpd_storm_ctl", &i915_hpd_storm_ctl_fops},
> >  	{"i915_ipc_status", &i915_ipc_status_fops},
> > -	{"i915_drrs_ctl", &i915_drrs_ctl_fops}
> > +	{"i915_drrs_ctl", &i915_drrs_ctl_fops},
> > +	{"i915_edp_psr_debug", &i915_edp_psr_debug_fops}
> >  };
> >  
> >  int i915_debugfs_register(struct drm_i915_private *dev_priv)
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index c9c3b2ba6a86..c0224a86344e 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -608,6 +608,7 @@ struct i915_psr {
> >  	bool colorimetry_support;
> >  	bool alpm;
> >  	bool has_hw_tracking;
> > +	bool debug;
> >  
> >  	void (*enable_source)(struct intel_dp *,
> >  			      const struct intel_crtc_state *);
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> > index 8a894adf2ca1..e5aaf805c6a8 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -2391,40 +2391,6 @@ static void ilk_display_irq_handler(struct drm_i915_private *dev_priv,
> >  		ironlake_rps_change_irq_handler(dev_priv);
> >  }
> >  
> > -static void hsw_edp_psr_irq_handler(struct drm_i915_private *dev_priv)
> > -{
> > -	u32 edp_psr_iir = I915_READ(EDP_PSR_IIR);
> > -	u32 edp_psr_imr = I915_READ(EDP_PSR_IMR);
> > -	u32 mask = BIT(TRANSCODER_EDP);
> > -	enum transcoder cpu_transcoder;
> > -
> > -	if (INTEL_GEN(dev_priv) >= 8)
> > -		mask |= BIT(TRANSCODER_A) |
> > -			BIT(TRANSCODER_B) |
> > -			BIT(TRANSCODER_C);
> > -
> > -	for_each_cpu_transcoder_masked(dev_priv, cpu_transcoder, mask) {
> > -		if (edp_psr_iir & EDP_PSR_ERROR(cpu_transcoder))
> > -			DRM_DEBUG_KMS("Transcoder %s PSR error\n",
> > -				      transcoder_name(cpu_transcoder));
> > -
> > -		if (edp_psr_iir & EDP_PSR_PRE_ENTRY(cpu_transcoder)) {
> > -			DRM_DEBUG_KMS("Transcoder %s PSR prepare entry in 2 vblanks\n",
> > -				      transcoder_name(cpu_transcoder));
> > -			edp_psr_imr |= EDP_PSR_PRE_ENTRY(cpu_transcoder);
> > -		}
> > -
> > -		if (edp_psr_iir & EDP_PSR_POST_EXIT(cpu_transcoder)) {
> > -			DRM_DEBUG_KMS("Transcoder %s PSR exit completed\n",
> > -				      transcoder_name(cpu_transcoder));
> > -			edp_psr_imr &= ~EDP_PSR_PRE_ENTRY(cpu_transcoder);
> > -		}
> > -	}
> > -
> > -	I915_WRITE(EDP_PSR_IMR, edp_psr_imr);
> > -	I915_WRITE(EDP_PSR_IIR, edp_psr_iir);
> > -}
> > -
> >  static void ivb_display_irq_handler(struct drm_i915_private *dev_priv,
> >  				    u32 de_iir)
> >  {
> > @@ -2437,8 +2403,12 @@ static void ivb_display_irq_handler(struct drm_i915_private *dev_priv,
> >  	if (de_iir & DE_ERR_INT_IVB)
> >  		ivb_err_int_handler(dev_priv);
> >  
> > -	if (de_iir & DE_EDP_PSR_INT_HSW)
> > -		hsw_edp_psr_irq_handler(dev_priv);
> > +	if (de_iir & DE_EDP_PSR_INT_HSW) {
> > +		u32 psr_iir = I915_READ(EDP_PSR_IIR);
> > +
> > +		intel_psr_irq_handler(dev_priv, psr_iir);
> > +		I915_WRITE(EDP_PSR_IIR, psr_iir);
> > +	}
> >  
> >  	if (de_iir & DE_AUX_CHANNEL_A_IVB)
> >  		dp_aux_irq_handler(dev_priv);
> > @@ -2580,7 +2550,10 @@ gen8_de_irq_handler(struct drm_i915_private *dev_priv, u32 master_ctl)
> >  			}
> >  
> >  			if (iir & GEN8_DE_EDP_PSR) {
> > -				hsw_edp_psr_irq_handler(dev_priv);
> > +				u32 psr_iir = I915_READ(EDP_PSR_IIR);
> > +
> > +				intel_psr_irq_handler(dev_priv, psr_iir);
> > +				I915_WRITE(EDP_PSR_IIR, psr_iir);
> >  				found = true;
> >  			}
> >  
> > @@ -3729,7 +3702,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
> >  
> >  	if (IS_HASWELL(dev_priv)) {
> >  		gen3_assert_iir_is_zero(dev_priv, EDP_PSR_IIR);
> > -		I915_WRITE(EDP_PSR_IMR, 0);
> > +		I915_WRITE(EDP_PSR_IMR, ~EDP_PSR_ERROR(TRANSCODER_EDP));
> >  		display_mask |= DE_EDP_PSR_INT_HSW;
> >  	}
> >  
> > @@ -3845,6 +3818,7 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
> >  	u32 de_port_enables;
> >  	u32 de_misc_masked = GEN8_DE_MISC_GSE | GEN8_DE_EDP_PSR;
> >  	enum pipe pipe;
> > +	u32 psr_masked;
> >  
> >  	if (INTEL_GEN(dev_priv) >= 9) {
> >  		de_pipe_masked |= GEN9_DE_PIPE_IRQ_FAULT_ERRORS;
> > @@ -3869,7 +3843,10 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
> >  		de_port_enables |= GEN8_PORT_DP_A_HOTPLUG;
> >  
> >  	gen3_assert_iir_is_zero(dev_priv, EDP_PSR_IIR);
> > -	I915_WRITE(EDP_PSR_IMR, 0);
> > +	psr_masked = EDP_PSR_ERROR(TRANSCODER_EDP) |
> > +		     EDP_PSR_ERROR(TRANSCODER_A) | EDP_PSR_ERROR(TRANSCODER_B) |
> > +		     EDP_PSR_ERROR(TRANSCODER_C);
> > +	I915_WRITE(EDP_PSR_IMR, ~psr_masked);
> >  
> >  	for_each_pipe(dev_priv, pipe) {
> >  		dev_priv->de_irq_mask[pipe] = ~de_pipe_masked;
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index a215aa78b0be..8be75cc5bf24 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1887,6 +1887,8 @@ void intel_psr_single_frame_update(struct drm_i915_private *dev_priv,
> >  				   unsigned frontbuffer_bits);
> >  void intel_psr_compute_config(struct intel_dp *intel_dp,
> >  			      struct intel_crtc_state *crtc_state);
> > +void intel_psr_debug_control(struct drm_i915_private *dev_priv, bool enable);
> > +void intel_psr_irq_handler(struct drm_i915_private *dev_priv, u32 psr_iir);
> >  
> >  /* intel_runtime_pm.c */
> >  int intel_power_domains_init(struct drm_i915_private *);
> > diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> > index b8e083e10029..fdc5e1bf198a 100644
> > --- a/drivers/gpu/drm/i915/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > @@ -93,6 +93,60 @@ static void psr_aux_io_power_put(struct intel_dp *intel_dp)
> >  	intel_display_power_put(dev_priv, psr_aux_domain(intel_dp));
> >  }
> >  
> > +void intel_psr_debug_control(struct drm_i915_private *dev_priv, bool enable)
> > +{
> > +	u32 mask;
> > +
> > +	/* No PSR interrupts on VLV/CHV */
> > +	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> > +		return;
> > +
> > +	mask = EDP_PSR_POST_EXIT(TRANSCODER_EDP) |
> > +	       EDP_PSR_PRE_ENTRY(TRANSCODER_EDP);
> > +
> > +	if (INTEL_GEN(dev_priv) >= 8)
> > +		mask |= EDP_PSR_POST_EXIT(TRANSCODER_A) |
> > +			EDP_PSR_PRE_ENTRY(TRANSCODER_A) |
> > +			EDP_PSR_POST_EXIT(TRANSCODER_B) |
> > +			EDP_PSR_PRE_ENTRY(TRANSCODER_B) |
> > +			EDP_PSR_POST_EXIT(TRANSCODER_C) |
> > +			EDP_PSR_PRE_ENTRY(TRANSCODER_C);
> > +
> > +	if (enable) {
> > +		WRITE_ONCE(dev_priv->psr.debug, true);
> > +		I915_WRITE(EDP_PSR_IMR, I915_READ(EDP_PSR_IMR) & ~mask);
> 
> Why RMW?
> 
Avoids updating this function when new PSR error bits are added in
i915_irq.c

Would you prefer 

mask |= EDP_PSR_ERROR(TRANCODER_A) | ...  here? 

I think this has started to look ugly already. The loop was concise IMO.

The other option is to

#define HSW_PSR_INTR_DBG_MASK = 0x7
#define BDW_PSR_INTR_DBG_MASK = 0x07070707 



> > +	} else {
> > +		I915_WRITE(EDP_PSR_IMR, I915_READ(EDP_PSR_IMR) | mask);
> > +		WRITE_ONCE(dev_priv->psr.debug, false);
> > +	}
> > +}
> > +
> > +void intel_psr_irq_handler(struct drm_i915_private *dev_priv, u32 psr_iir)
> > +{
> > +	u32 transcoders = BIT(TRANSCODER_EDP);
> > +	enum transcoder cpu_transcoder;
> > +
> > +	if (INTEL_GEN(dev_priv) >= 8)
> > +		transcoders |= BIT(TRANSCODER_A) |
> > +			       BIT(TRANSCODER_B) |
> > +			       BIT(TRANSCODER_C);
> > +
> > +	for_each_cpu_transcoder_masked(dev_priv, cpu_transcoder, transcoders) {
> > +		/* FIXME: Exit PSR when this happens. */
> 
> Should this maybe say "retrain the link manually when this happens"?
> 

Yeah, we should do both in fact. Makes sense to exit PSR, link train
manually and keep it disabled.



> > +		if (psr_iir & EDP_PSR_ERROR(cpu_transcoder))
> > +			DRM_DEBUG_KMS("[transcoder %s] PSR aux error\n",
> > +				      transcoder_name(cpu_transcoder));
> > +
> > +		if (psr_iir & EDP_PSR_PRE_ENTRY(cpu_transcoder))
> > +			DRM_DEBUG_KMS("[transcoder %s] PSR entry attempt in 2 vblanks\n",
> > +				      transcoder_name(cpu_transcoder));
> > +
> > +		if (psr_iir & EDP_PSR_POST_EXIT(cpu_transcoder))
> > +			DRM_DEBUG_KMS("[transcoder %s] PSR exit completed\n",
> > +				      transcoder_name(cpu_transcoder));
> > +	}
> > +}
> > +
> >  static bool intel_dp_get_y_cord_status(struct intel_dp *intel_dp)
> >  {
> >  	uint8_t psr_caps = 0;
> > -- 
> > 2.14.1
> 


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