[Intel-gfx] [DMC_BUGFIX_V3] drm/i915/skl: Making DC6 entry is the last call in suspend flow.

Daniel Vetter daniel at ffwll.ch
Mon Oct 19 02:26:19 PDT 2015


On Fri, Oct 16, 2015 at 03:22:45PM +0300, Imre Deak wrote:
> On ti, 2015-09-29 at 11:01 +0530, Animesh Manna wrote:
> > Mmio register access after dc6/dc5 entry is not allowed when
> > DC6 power states are enabled according to bspec (bspec-id 0527),
> > so enabling dc6 as the last call in suspend flow.
> > 
> > v1: Initial version.
> > 
> > v2: Based on review comment from Daniel,
> > - created a seperate patch for csr uninitialization set call.
> > 
> > v3: Rebased on top of latest code.
> > 
> > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Damien Lespiau <damien.lespiau at intel.com>
> > Cc: Imre Deak <imre.deak at intel.com>
> > Cc: Sunil Kamath <sunil.kamath at intel.com>
> > Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> > Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju at intel.com>
> > Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj at intel.com>
> 
> Acked-by: Imre Deak <imre.deak at intel.com>
> 
> Suggestion for the commit message:
> 
> Currently we keep DC6 enabled during modesets and DPAUX transfers, which
> is not allowed according to the specification. This can lead at least to
> PLL locking failures, DPAUX timeouts and prevent deeper package power
> states (PC9/10). Fix this for now by enabling DC6 only when we know the
> above events (modeset, DPAUX) can't happen.
> 
> This a temporary solution as some issues are still unsolved as described
> in [1] and [2], we'll address those as a follow-up. 
> 
> [1]
> http://lists.freedesktop.org/archives/intel-gfx/2015-October/077669.html
> [2]
> http://lists.freedesktop.org/archives/intel-gfx/2015-October/077787.html

Queued for -next, thanks for the patch.
-Daniel

> 
> 
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c         | 13 +++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h        |  2 ++
> >  drivers/gpu/drm/i915/intel_runtime_pm.c | 19 +++++++------------
> >  3 files changed, 22 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index 1cb6b82..51075d5 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -1049,10 +1049,20 @@ static int i915_pm_resume(struct device *dev)
> >  
> >  static int skl_suspend_complete(struct drm_i915_private *dev_priv)
> >  {
> > +	enum csr_state state;
> >  	/* Enabling DC6 is not a hard requirement to enter runtime D3 */
> >  
> >  	skl_uninit_cdclk(dev_priv);
> >  
> > +	/* TODO: wait for a completion event or
> > +	 * similar here instead of busy
> > +	 * waiting using wait_for function.
> > +	 */
> > +	wait_for((state = intel_csr_load_status_get(dev_priv)) !=
> > +			FW_UNINITIALIZED, 1000);
> > +	if (state == FW_LOADED)
> > +		skl_enable_dc6(dev_priv);
> > +
> >  	return 0;
> >  }
> >  
> > @@ -1099,6 +1109,9 @@ static int skl_resume_prepare(struct drm_i915_private *dev_priv)
> >  {
> >  	struct drm_device *dev = dev_priv->dev;
> >  
> > +	if (intel_csr_load_status_get(dev_priv) == FW_LOADED)
> > +		skl_disable_dc6(dev_priv);
> > +
> >  	skl_init_cdclk(dev_priv);
> >  	intel_csr_load_program(dev);
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index c96289d..990161d 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1143,6 +1143,8 @@ void bxt_enable_dc9(struct drm_i915_private *dev_priv);
> >  void bxt_disable_dc9(struct drm_i915_private *dev_priv);
> >  void skl_init_cdclk(struct drm_i915_private *dev_priv);
> >  void skl_uninit_cdclk(struct drm_i915_private *dev_priv);
> > +void skl_enable_dc6(struct drm_i915_private *dev_priv);
> > +void skl_disable_dc6(struct drm_i915_private *dev_priv);
> >  void intel_dp_get_m_n(struct intel_crtc *crtc,
> >  		      struct intel_crtc_state *pipe_config);
> >  void intel_dp_set_m_n(struct intel_crtc *crtc, enum link_m_n_set m_n);
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > index d8e9416..d6b4f61 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > @@ -551,7 +551,7 @@ static void assert_can_disable_dc6(struct drm_i915_private *dev_priv)
> >  		  "DC6 already programmed to be disabled.\n");
> >  }
> >  
> > -static void skl_enable_dc6(struct drm_i915_private *dev_priv)
> > +void skl_enable_dc6(struct drm_i915_private *dev_priv)
> >  {
> >  	uint32_t val;
> >  
> > @@ -568,7 +568,7 @@ static void skl_enable_dc6(struct drm_i915_private *dev_priv)
> >  	POSTING_READ(DC_STATE_EN);
> >  }
> >  
> > -static void skl_disable_dc6(struct drm_i915_private *dev_priv)
> > +void skl_disable_dc6(struct drm_i915_private *dev_priv)
> >  {
> >  	uint32_t val;
> >  
> > @@ -629,10 +629,10 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
> >  				!I915_READ(HSW_PWR_WELL_BIOS),
> >  				"Invalid for power well status to be enabled, unless done by the BIOS, \
> >  				when request is to disable!\n");
> > -			if ((GEN9_ENABLE_DC5(dev) || SKL_ENABLE_DC6(dev)) &&
> > -				power_well->data == SKL_DISP_PW_2) {
> > +			if (power_well->data == SKL_DISP_PW_2) {
> > +				if (GEN9_ENABLE_DC5(dev))
> > +					gen9_disable_dc5(dev_priv);
> >  				if (SKL_ENABLE_DC6(dev)) {
> > -					skl_disable_dc6(dev_priv);
> >  					/*
> >  					 * DDI buffer programming unnecessary during driver-load/resume
> >  					 * as it's already done during modeset initialization then.
> > @@ -640,8 +640,6 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
> >  					 */
> >  					if (!dev_priv->power_domains.initializing)
> >  						intel_prepare_ddi(dev);
> > -				} else {
> > -					gen9_disable_dc5(dev_priv);
> >  				}
> >  			}
> >  			I915_WRITE(HSW_PWR_WELL_DRIVER, tmp | req_mask);
> > @@ -667,7 +665,7 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
> >  				DRM_DEBUG_KMS("Disabling %s\n", power_well->name);
> >  			}
> >  
> > -			if ((GEN9_ENABLE_DC5(dev) || SKL_ENABLE_DC6(dev)) &&
> > +			if (GEN9_ENABLE_DC5(dev) &&
> >  				power_well->data == SKL_DISP_PW_2) {
> >  				enum csr_state state;
> >  				/* TODO: wait for a completion event or
> > @@ -680,10 +678,7 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
> >  					DRM_DEBUG("CSR firmware not ready (%d)\n",
> >  							state);
> >  				else
> > -					if (SKL_ENABLE_DC6(dev))
> > -						skl_enable_dc6(dev_priv);
> > -					else
> > -						gen9_enable_dc5(dev_priv);
> > +					gen9_enable_dc5(dev_priv);
> >  			}
> >  		}
> >  	}
> 
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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