| Message ID | 1432660960-8979-4-git-send-email-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/26/2015 10:22 AM, ville.syrjala@linux.intel.com wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Switch from using 31 PFI credits to 63 PFI credits when cdclk>=czclk on > CHV. The spec lists both 31 and 63 as "suggested" values, but based on > feedback from hardware folks we should actually be using 63. Originally > I picked the 31 basically by flipping a coin. > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/intel_display.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 067b1de..44b9c54 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -5986,7 +5986,7 @@ static void vlv_program_pfi_credits(struct drm_i915_private *dev_priv) > if (DIV_ROUND_CLOSEST(dev_priv->cdclk_freq, 1000) >= dev_priv->rps.cz_freq) { > /* CHV suggested value is 31 or 63 */ > if (IS_CHERRYVIEW(dev_priv)) > - credits = PFI_CREDIT_31; > + credits = PFI_CREDIT_63; > else > credits = PFI_CREDIT(15); > } else { > Although not part of this review the else clause is setting PFI_CREDIT to 15 when the BPSEC states that the default of 8 should be used when cdclk/czclk < 1. According to the original patch, 15 is the optimal value as stated by another driver team. Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
On Fri, Jun 12, 2015 at 09:24:24AM -0700, Clint Taylor wrote: > On 05/26/2015 10:22 AM, ville.syrjala@linux.intel.com wrote: > >From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > > >Switch from using 31 PFI credits to 63 PFI credits when cdclk>=czclk on > >CHV. The spec lists both 31 and 63 as "suggested" values, but based on > >feedback from hardware folks we should actually be using 63. Originally > >I picked the 31 basically by flipping a coin. > > > >Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > >--- > > drivers/gpu/drm/i915/intel_display.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > >diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > >index 067b1de..44b9c54 100644 > >--- a/drivers/gpu/drm/i915/intel_display.c > >+++ b/drivers/gpu/drm/i915/intel_display.c > >@@ -5986,7 +5986,7 @@ static void vlv_program_pfi_credits(struct drm_i915_private *dev_priv) > > if (DIV_ROUND_CLOSEST(dev_priv->cdclk_freq, 1000) >= dev_priv->rps.cz_freq) { > > /* CHV suggested value is 31 or 63 */ > > if (IS_CHERRYVIEW(dev_priv)) > >- credits = PFI_CREDIT_31; > >+ credits = PFI_CREDIT_63; > > else > > credits = PFI_CREDIT(15); > > } else { > > > > Although not part of this review the else clause is setting PFI_CREDIT to 15 > when the BPSEC states that the default of 8 should be used when cdclk/czclk > < 1. According to the original patch, 15 is the optimal value as stated by > another driver team. Can you please file a bspec correction notice to fix the issue with the 15 vs. 8? > Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com> Queued for -next, thanks for the patch. -Daniel
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 067b1de..44b9c54 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -5986,7 +5986,7 @@ static void vlv_program_pfi_credits(struct drm_i915_private *dev_priv) if (DIV_ROUND_CLOSEST(dev_priv->cdclk_freq, 1000) >= dev_priv->rps.cz_freq) { /* CHV suggested value is 31 or 63 */ if (IS_CHERRYVIEW(dev_priv)) - credits = PFI_CREDIT_31; + credits = PFI_CREDIT_63; else credits = PFI_CREDIT(15); } else {