Re: [PATCH v3 4/6] drm/i915/crc: Make IPS workaround generic

["Souza, Jose" <jose.souza@intel.com>]

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On Thu, 2019-02-28 at 18:56 +0200, Ville Syrjälä wrote:
> On Wed, Feb 27, 2019 at 05:32:57PM -0800, José Roberto de Souza
> wrote:
> > Other features like PSR2 also needs to be disabled while getting
> > CRC
> > so lets rename ips_force_disable to crc_enabled, drop all this
> > checks
> > for pipe A and HSW and BDW and make it generic and
> > hsw_compute_ips_config() will take care of all the checks removed
> > from here.
> > 
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c  | 10 +++++--
> >  drivers/gpu/drm/i915/intel_drv.h      |  3 +-
> >  drivers/gpu/drm/i915/intel_pipe_crc.c | 42 +++++++++------------
> > ------
> >  3 files changed, 24 insertions(+), 31 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 816e8f124b3b..328967c642b3 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -6751,7 +6751,13 @@ static bool hsw_compute_ips_config(struct
> > intel_crtc_state *crtc_state)
> >  	if (!hsw_crtc_state_ips_capable(crtc_state))
> >  		return false;
> >  
> > -	if (crtc_state->ips_force_disable)
> > +	/*
> > +	 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
> > +	 * enabled and disabled dynamically based on package C states,
> > +	 * user space can't make reliable use of the CRCs, so let's
> > just
> > +	 * completely disable it.
> > +	 */
> > +	if (crtc_state->crc_enabled)
> >  		return false;
> 
> Hmm. I was wondering how we even manage to pass the state checker
> with
> the current code. But apparently we don't have state checking for
> IPS.
> I would suggest moving this into hsw_compute_ips_config() and then
> adding the state checker (for HSW only though since BDW can't do the
> readout).
> 
> >  
> >  	/* IPS should be fine as long as at least one plane is enabled.
> > */
> > @@ -11684,7 +11690,7 @@ clear_intel_crtc_state(struct
> > intel_crtc_state *crtc_state)
> >  	saved_state->shared_dpll = crtc_state->shared_dpll;
> >  	saved_state->dpll_hw_state = crtc_state->dpll_hw_state;
> >  	saved_state->pch_pfit.force_thru = crtc_state-
> > >pch_pfit.force_thru;
> > -	saved_state->ips_force_disable = crtc_state->ips_force_disable;
> > +	saved_state->crc_enabled = crtc_state->crc_enabled;
> >  	if (IS_G4X(dev_priv) ||
> >  	    IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> >  		saved_state->wm = crtc_state->wm;
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index 5412373e2f98..2be64529e4a2 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -999,7 +999,8 @@ struct intel_crtc_state {
> >  	struct intel_link_m_n fdi_m_n;
> >  
> >  	bool ips_enabled;
> > -	bool ips_force_disable;
> > +
> > +	bool crc_enabled;
> >  
> >  	bool enable_fbc;
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c
> > b/drivers/gpu/drm/i915/intel_pipe_crc.c
> > index 53d4ec68d3c4..f6d0b2aaffe2 100644
> > --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
> > +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
> > @@ -280,11 +280,12 @@ static int ilk_pipe_crc_ctl_reg(enum
> > intel_pipe_crc_source *source,
> >  	return 0;
> >  }
> >  
> > -static void hsw_pipe_A_crc_wa(struct drm_i915_private *dev_priv,
> > -			      bool enable)
> > +static void
> > +intel_crtc_crc_prepare(struct drm_i915_private *dev_priv, struct
> > drm_crtc *crtc,
> 
> Just pass in the intel_crtc

Okay

> 
> > +		       bool enable)
> >  {
> >  	struct drm_device *dev = &dev_priv->drm;
> > -	struct intel_crtc *crtc = intel_get_crtc_for_pipe(dev_priv,
> > PIPE_A);
> > +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> 
> and then we don't have to have an ugly name for this.
> 
> Also pasing in dev_priv is redundant when you're already passing in
> the
> crtc.
> 

okay

> The function name isn't super descriptive. It makes me think we're
> preparing for CRC capture, when in fact it just adds/removes the
> w/as.

What about: intel_crtc_crc_workarounds_setup()?

> 
> >  	struct intel_crtc_state *pipe_config;
> >  	struct drm_atomic_state *state;
> >  	struct drm_modeset_acquire_ctx ctx;
> > @@ -301,23 +302,15 @@ static void hsw_pipe_A_crc_wa(struct
> > drm_i915_private *dev_priv,
> >  	state->acquire_ctx = &ctx;
> >  
> >  retry:
> > -	pipe_config = intel_atomic_get_crtc_state(state, crtc);
> > +	pipe_config = intel_atomic_get_crtc_state(state, intel_crtc);
> >  	if (IS_ERR(pipe_config)) {
> >  		ret = PTR_ERR(pipe_config);
> >  		goto put_state;
> >  	}
> >  
> > -	if (HAS_IPS(dev_priv)) {
> > -		/*
> > -		 * When IPS gets enabled, the pipe CRC changes. Since
> > IPS gets
> > -		 * enabled and disabled dynamically based on package C
> > states,
> > -		 * user space can't make reliable use of the CRCs, so
> > let's just
> > -		 * completely disable it.
> > -		 */
> > -		pipe_config->ips_force_disable = enable;
> > -	}
> > +	pipe_config->crc_enabled = enable;
> >  
> > -	if (IS_HASWELL(dev_priv)) {
> > +	if (IS_HASWELL(dev_priv) && intel_crtc->pipe == PIPE_A) {
> >  		pipe_config->pch_pfit.force_thru = enable;
> >  		if (pipe_config->cpu_transcoder == TRANSCODER_EDP &&
> >  		    pipe_config->pch_pfit.enabled != enable)
> > @@ -343,8 +336,7 @@ static void hsw_pipe_A_crc_wa(struct
> > drm_i915_private *dev_priv,
> >  static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
> >  				enum pipe pipe,
> >  				enum intel_pipe_crc_source *source,
> > -				u32 *val,
> > -				bool set_wa)
> > +				u32 *val)
> >  {
> >  	if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
> >  		*source = INTEL_PIPE_CRC_SOURCE_PIPE;
> > @@ -357,10 +349,6 @@ static int ivb_pipe_crc_ctl_reg(struct
> > drm_i915_private *dev_priv,
> >  		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_IVB;
> >  		break;
> >  	case INTEL_PIPE_CRC_SOURCE_PIPE:
> > -		if (set_wa && (IS_HASWELL(dev_priv) ||
> > -		     IS_BROADWELL(dev_priv)) && pipe == PIPE_A)
> > -			hsw_pipe_A_crc_wa(dev_priv, true);
> > -
> >  		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_PF_IVB;
> >  		break;
> >  	case INTEL_PIPE_CRC_SOURCE_NONE:
> > @@ -418,8 +406,7 @@ static int skl_pipe_crc_ctl_reg(struct
> > drm_i915_private *dev_priv,
> >  
> >  static int get_new_crc_ctl_reg(struct drm_i915_private *dev_priv,
> >  			       enum pipe pipe,
> > -			       enum intel_pipe_crc_source *source, u32
> > *val,
> > -			       bool set_wa)
> > +			       enum intel_pipe_crc_source *source, u32
> > *val)
> >  {
> >  	if (IS_GEN(dev_priv, 2))
> >  		return i8xx_pipe_crc_ctl_reg(source, val);
> > @@ -430,7 +417,7 @@ static int get_new_crc_ctl_reg(struct
> > drm_i915_private *dev_priv,
> >  	else if (IS_GEN_RANGE(dev_priv, 5, 6))
> >  		return ilk_pipe_crc_ctl_reg(source, val);
> >  	else if (INTEL_GEN(dev_priv) < 9)
> > -		return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source,
> > val, set_wa);
> > +		return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source,
> > val);
> >  	else
> >  		return skl_pipe_crc_ctl_reg(dev_priv, pipe, source,
> > val);
> >  }
> > @@ -618,7 +605,9 @@ int intel_crtc_set_crc_source(struct drm_crtc
> > *crtc, const char *source_name)
> >  		return -EIO;
> >  	}
> >  
> > -	ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source, &val,
> > true);
> > +	intel_crtc_crc_prepare(dev_priv, crtc, source !=
> > INTEL_PIPE_CRC_SOURCE_NONE);
> > +
> 
> Aren't we potentially corrupting the last CRC(s) by turning off the
> w/as
> before disbling CRC capture?

It will only be NULL when uses closes the file descriptor to CRC data,
so even if its corrupted user will never get those CRCs.

> 
> > +	ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source,
> > &val);
> >  	if (ret != 0)
> >  		goto out;
> >  
> > @@ -629,9 +618,6 @@ int intel_crtc_set_crc_source(struct drm_crtc
> > *crtc, const char *source_name)
> >  	if (!source) {
> >  		if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> >  			vlv_undo_pipe_scramble_reset(dev_priv, crtc-
> > >index);
> > -		else if ((IS_HASWELL(dev_priv) ||
> > -			  IS_BROADWELL(dev_priv)) && crtc->index ==
> > PIPE_A)
> > -			hsw_pipe_A_crc_wa(dev_priv, false);
> >  	}
> >  
> >  	pipe_crc->skipped = 0;
> > @@ -652,7 +638,7 @@ void intel_crtc_enable_pipe_crc(struct
> > intel_crtc *intel_crtc)
> >  	if (!crtc->crc.opened)
> >  		return;
> >  
> > -	if (get_new_crc_ctl_reg(dev_priv, crtc->index, &pipe_crc-
> > >source, &val, false) < 0)
> > +	if (get_new_crc_ctl_reg(dev_priv, crtc->index, &pipe_crc-
> > >source, &val) < 0)
> >  		return;
> >  
> >  	/* Don't need pipe_crc->lock here, IRQs are not generated. */
> > -- 
> > 2.21.0

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