On Wed, Mar 09, 2022 at 06:49:41PM +0200, Ville Syrjala wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > For modern platforms the spec explicitly states that a > SAGV block time of zero means that SAGV is not supported. > Let's extend that to all platforms. Supposedly there should > be no systems where this isn't true, and it'll allow us to: > - use the same code regardless of older vs. newer platform > - wm latencies already treat 0 as disabled, so this fits well > with other related code > - make it a bit more clear when SAGV is used vs. not > - avoid overflows from adding U32_MAX with a u16 wm0 latency value > which could cause us to miscalculate the SAGV watermarks on tgl+ > > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_pm.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c > index 8ee31c9590a7..40a3094e55ca 100644 > --- a/drivers/gpu/drm/i915/intel_pm.c > +++ b/drivers/gpu/drm/i915/intel_pm.c > @@ -3696,8 +3696,7 @@ skl_setup_sagv_block_time(struct drm_i915_private *dev_priv) > MISSING_CASE(DISPLAY_VER(dev_priv)); > } > > - /* Default to an unusable block time */ > - dev_priv->sagv_block_time_us = -1; > + dev_priv->sagv_block_time_us = 0; > } > > /* > @@ -5644,7 +5643,7 @@ static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state, > result->min_ddb_alloc = max(min_ddb_alloc, blocks) + 1; > result->enable = true; > > - if (DISPLAY_VER(dev_priv) < 12) > + if (DISPLAY_VER(dev_priv) < 12 && dev_priv->sagv_block_time_us) > result->can_sagv = latency >= dev_priv->sagv_block_time_us; > } > > @@ -5677,7 +5676,10 @@ static void tgl_compute_sagv_wm(const struct intel_crtc_state *crtc_state, > struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev); > struct skl_wm_level *sagv_wm = &plane_wm->sagv.wm0; > struct skl_wm_level *levels = plane_wm->wm; > - unsigned int latency = dev_priv->wm.skl_latency[0] + dev_priv->sagv_block_time_us; > + unsigned int latency = 0; > + > + if (dev_priv->sagv_block_time_us) > + latency = dev_priv->sagv_block_time_us + dev_priv->wm.skl_latency[0]; Should we may be add this to intel_has_sagv? I thought this was supposed to tell, if SAGV is supported or not. Should we just call it hear as well, may be.. Now we kinda making it less obvious. Stan > > skl_compute_plane_wm(crtc_state, plane, 0, latency, > wm_params, &levels[0], > -- > 2.34.1 >
