[Intel-gfx] [PATCH 06/11] drm/i915: Match all PSR mode entry conditions before enabling it.

[Daniel Vetter]

On Mon, Jul 15, 2013 at 03:06:22PM +0100, Chris Wilson wrote:
> On Thu, Jul 11, 2013 at 06:45:00PM -0300, Rodrigo Vivi wrote:
> > v2: Prefer seq_puts to seq_printf by Paulo Zanoni.
> > v3: small changes like avoiding calling dp_to_dig_port twice as noticed by
> >     Paulo Zanoni.
> > v4: Avoiding reading non-existent registers - noticed by Paulo
> >     on first psr debugfs patch.
> > v5: Accepting more suggestions from Paulo:
> >     * check sw interlace flag instead of i915_read
> >     * introduce PSR_S3D_ENABLED to avoid forgeting it whenever added.
> > 
> > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
> > ---
> >  drivers/gpu/drm/i915/i915_debugfs.c | 44 ++++++++++++++++++----
> >  drivers/gpu/drm/i915/i915_drv.h     | 13 +++++++
> >  drivers/gpu/drm/i915/i915_reg.h     |  7 ++++
> >  drivers/gpu/drm/i915/intel_dp.c     | 74 ++++++++++++++++++++++++++++++++++++-
> >  4 files changed, 130 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > index fe3cd5a..e679968 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -1948,17 +1948,47 @@ static int i915_edp_psr_status(struct seq_file *m, void *data)
> >  	struct drm_info_node *node = m->private;
> >  	struct drm_device *dev = node->minor->dev;
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > -	u32 psrctl, psrstat, psrperf;
> > +	u32 psrstat, psrperf;
> >  
> > -	if (!IS_HASWELL(dev)) {
> > -		seq_puts(m, "PSR not supported on this platform\n");
> > +	if (IS_HASWELL(dev) && I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE) {
> > +		seq_puts(m, "PSR enabled\n");
> > +	} else {
> > +		seq_puts(m, "PSR disabled: ");
> > +		switch (dev_priv->no_psr_reason) {
> > +		case PSR_NO_SOURCE:
> 
> I am not a fan of using a continually expanding set of enums for
> no_psr_reason (and no_fbc_reason). If we just stored a const char
> *no_psr_reason, it would make like much easier for us (fewer lines and a
> smaller object).
> 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index d4b52a9..c0bd887 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1497,11 +1497,83 @@ static void intel_edp_psr_enable_source(struct intel_dp *intel_dp)
> >  		   EDP_PSR_ENABLE);
> >  }
> >  
> > +static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
> > +{
> > +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> > +	struct drm_device *dev = dig_port->base.base.dev;
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > +	struct drm_crtc *crtc = dig_port->base.base.crtc;
> > +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> > +	struct drm_i915_gem_object *obj = to_intel_framebuffer(crtc->fb)->obj;
> > +	struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
> > +
> > +	if (!IS_HASWELL(dev)) {
> > +		DRM_DEBUG_KMS("PSR not supported on this platform\n");
> > +		dev_priv->no_psr_reason = PSR_NO_SOURCE;
> > +		return false;
> > +	}
> > +
> > +	if ((intel_encoder->type != INTEL_OUTPUT_EDP) ||
> > +	    (dig_port->port != PORT_A)) {
> > +		DRM_DEBUG_KMS("HSW ties PSR to DDI A (eDP)\n");
> > +		dev_priv->no_psr_reason = PSR_HSW_NOT_DDIA;
> > +		return false;
> > +	}
> > +
> > +	if (!is_edp_psr(intel_dp)) {
> > +		DRM_DEBUG_KMS("PSR not supported by this panel\n");
> > +		dev_priv->no_psr_reason = PSR_NO_SINK;
> > +		return false;
> > +	}
> > +
> > +	if (!intel_crtc->active || !crtc->fb || !crtc->mode.clock) {
> > +		DRM_DEBUG_KMS("crtc not active for PSR\n");
> > +		dev_priv->no_psr_reason = PSR_CRTC_NOT_ACTIVE;
> > +		return false;
> > +	}
> > +
> > +	if ((I915_READ(HSW_PWR_WELL_DRIVER) & HSW_PWR_WELL_ENABLE) ||
> > +	    (I915_READ(HSW_PWR_WELL_KVMR) & HSW_PWR_WELL_ENABLE)) {
> 
> Any time we resort to reading back register state is a failure in our
> state tracking (and pipe_config).

Highly agreed, especially if it's a resource which is out of our control
like the KVMR bits. Since that's just plain broken I've removed it from
the patch.
-Daniel

> -Chris
> 
> -- 
> Chris Wilson, Intel Open Source Technology Centre
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch