On Wed, Nov 09, 2022 at 09:37:24PM -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. > > Cc: Matt Roper <[email protected]> > Suggested-by: Ville Syrjälä <[email protected]> > Signed-off-by: Anusha Srivatsa <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_cdclk.c | 2 ++ > drivers/gpu/drm/i915/display/intel_cdclk.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c > b/drivers/gpu/drm/i915/display/intel_cdclk.c > index 8a9031012d74..91112d266763 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > @@ -1962,6 +1962,8 @@ static bool intel_cdclk_can_crawl(struct > drm_i915_private *dev_priv, > if (!HAS_CDCLK_CRAWL(dev_priv)) > return false; > > + if (intel_pll_is_unknown(a->vco)) > + return false;
I think this guy is only called from the atomic_check() path, so this check shouldn't be needed here. Where we do need it is the crawl check bxt_set_cdclk() since that is what gets called directly from the sanitize() path with hw.vco=~0. > /* > * The vco and cd2x divider will change independently > * from each, so we disallow cd2x change when crawling. > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h > b/drivers/gpu/drm/i915/display/intel_cdclk.h > index c674879a84a5..6eb83d806f11 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.h > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h > @@ -80,6 +80,7 @@ intel_atomic_get_cdclk_state(struct intel_atomic_state > *state); > to_intel_cdclk_state(intel_atomic_get_old_global_obj_state(state, > &to_i915(state->base.dev)->display.cdclk.obj)) > #define intel_atomic_get_new_cdclk_state(state) \ > to_intel_cdclk_state(intel_atomic_get_new_global_obj_state(state, > &to_i915(state->base.dev)->display.cdclk.obj)) > +#define intel_pll_is_unknown(vco) ((vco) == ~0) > > int intel_cdclk_init(struct drm_i915_private *dev_priv); > > -- > 2.25.1 -- Ville Syrjälä Intel
