| Message ID | 20221111192602.257418-1-anusha.srivatsa@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/display: Add missing checks for cdclk crawling | expand |
On Fri, Nov 11, 2022 at 11:26:02AM -0800, Anusha Srivatsa wrote: > cdclk_sanitize() function was written assuming vco was a signed integer. > vco gets assigned to -1 (essentially ~0) for the case where PLL > might be enabled and vco is not a frequency that will ever > get used. In such a scenario the right thing to do is disable the > PLL and re-enable it again with a valid frequency. > However the vco is declared as a unsigned variable. > With the above assumption, driver takes crawl path when not needed. > Add explicit check to not crawl in the case of an invalid PLL. > > v2: Move the check from .h to .c (MattR) > - Move check to bxt_set_cdclk() instead of > intel_modeset_calc_cdclk() which is directly in > the path of the sanitize() function (Ville) > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> > Cc: Matt Roper <matthew.d.roper@intel.com> > Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com> > --- > drivers/gpu/drm/i915/display/intel_cdclk.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c > index 8a9031012d74..2d9b7ba58358 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > @@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct drm_i915_private *i915, > intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl); > } > > +static bool cdclk_pll_is_unknown(unsigned int vco) > +{ > + /* > + * Ensure driver does not take the crawl path for the > + * case when the vco is set to ~0 in the > + * sanitize path. > + */ > + return (vco == ~0); Pointless parens. > +} > + > static void bxt_set_cdclk(struct drm_i915_private *dev_priv, > const struct intel_cdclk_config *cdclk_config, > enum pipe pipe) > @@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv, > return; > } > > - if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0) { > + if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0 && > + (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) { More pointless parens With those removed Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Though I think we should probably add the pll_is_enabled() helper too, just make the code a bit more self explanatory. > if (dev_priv->display.cdclk.hw.vco != vco) > adlp_cdclk_pll_crawl(dev_priv, vco); > } else if (DISPLAY_VER(dev_priv) >= 11) > -- > 2.25.1
> -----Original Message----- > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > Sent: Friday, November 11, 2022 11:40 AM > To: Srivatsa, Anusha <anusha.srivatsa@intel.com> > Cc: intel-gfx@lists.freedesktop.org; Roper, Matthew D > <matthew.d.roper@intel.com> > Subject: Re: [PATCH] drm/i915/display: Add missing checks for cdclk crawling > > On Fri, Nov 11, 2022 at 11:26:02AM -0800, Anusha Srivatsa wrote: > > cdclk_sanitize() function was written assuming vco was a signed integer. > > vco gets assigned to -1 (essentially ~0) for the case where PLL might > > be enabled and vco is not a frequency that will ever get used. In such > > a scenario the right thing to do is disable the PLL and re-enable it > > again with a valid frequency. > > However the vco is declared as a unsigned variable. > > With the above assumption, driver takes crawl path when not needed. > > Add explicit check to not crawl in the case of an invalid PLL. > > > > v2: Move the check from .h to .c (MattR) > > - Move check to bxt_set_cdclk() instead of > > intel_modeset_calc_cdclk() which is directly in the path of the > > sanitize() function (Ville) > > > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Cc: Matt Roper <matthew.d.roper@intel.com> > > Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com> > > --- > > drivers/gpu/drm/i915/display/intel_cdclk.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c > > b/drivers/gpu/drm/i915/display/intel_cdclk.c > > index 8a9031012d74..2d9b7ba58358 100644 > > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > > @@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct > drm_i915_private *i915, > > intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl); } > > > > +static bool cdclk_pll_is_unknown(unsigned int vco) { > > + /* > > + * Ensure driver does not take the crawl path for the > > + * case when the vco is set to ~0 in the > > + * sanitize path. > > + */ > > + return (vco == ~0); > > Pointless parens. > > > +} > > + > > static void bxt_set_cdclk(struct drm_i915_private *dev_priv, > > const struct intel_cdclk_config *cdclk_config, > > enum pipe pipe) > > @@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private > *dev_priv, > > return; > > } > > > > - if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > > 0 && vco > 0) { > > + if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > > 0 && vco > 0 && > > + (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) { > > More pointless parens > > With those removed > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Thanks Ville. > Though I think we should probably add the pll_is_enabled() helper too, just > make the code a bit more self explanatory. At this point the current code should atleast not block the MTL cdclk churn series. But the suggested helper will make the code more explanatory and I can take it up. Thanks for the feedback! Anusha > > if (dev_priv->display.cdclk.hw.vco != vco) > > adlp_cdclk_pll_crawl(dev_priv, vco); > > } else if (DISPLAY_VER(dev_priv) >= 11) > > -- > > 2.25.1 > > -- > Ville Syrjälä > Intel
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c index 8a9031012d74..2d9b7ba58358 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.c +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c @@ -1716,6 +1716,16 @@ static void dg2_cdclk_squash_program(struct drm_i915_private *i915, intel_de_write(i915, CDCLK_SQUASH_CTL, squash_ctl); } +static bool cdclk_pll_is_unknown(unsigned int vco) +{ + /* + * Ensure driver does not take the crawl path for the + * case when the vco is set to ~0 in the + * sanitize path. + */ + return (vco == ~0); +} + static void bxt_set_cdclk(struct drm_i915_private *dev_priv, const struct intel_cdclk_config *cdclk_config, enum pipe pipe) @@ -1748,7 +1758,8 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv, return; } - if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0) { + if (HAS_CDCLK_CRAWL(dev_priv) && dev_priv->display.cdclk.hw.vco > 0 && vco > 0 && + (!cdclk_pll_is_unknown(dev_priv->display.cdclk.hw.vco))) { if (dev_priv->display.cdclk.hw.vco != vco) adlp_cdclk_pll_crawl(dev_priv, vco); } else if (DISPLAY_VER(dev_priv) >= 11)
cdclk_sanitize() function was written assuming vco was a signed integer. vco gets assigned to -1 (essentially ~0) for the case where PLL might be enabled and vco is not a frequency that will ever get used. In such a scenario the right thing to do is disable the PLL and re-enable it again with a valid frequency. However the vco is declared as a unsigned variable. With the above assumption, driver takes crawl path when not needed. Add explicit check to not crawl in the case of an invalid PLL. v2: Move the check from .h to .c (MattR) - Move check to bxt_set_cdclk() instead of intel_modeset_calc_cdclk() which is directly in the path of the sanitize() function (Ville) Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Matt Roper <matthew.d.roper@intel.com> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com> --- drivers/gpu/drm/i915/display/intel_cdclk.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)