On Mon, Sep 01, 2014 at 11:23:20AM +0300, Ville Syrjälä wrote:
> On Thu, Jul 10, 2014 at 08:31:21PM +0100, Chris Wilson wrote:
> > Rewrite commit 31685c258e0b0ad6aa486c5ec001382cf8a64212
> > Author: Deepak S <deepak.s@xxxxxxxxxxxxxxx>
> > Date: Thu Jul 3 17:33:01 2014 -0400
> >
> > drm/i915/vlv: WA for Turbo and RC6 to work together.
> >
> > Other than code clarity, the major improvement is to disable the extra
> > interrupts generated when idle. However, the reclocking remains rather
> > slow under the new manual regime, in particular it fails to downclock as
> > quickly as desired.
> >
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > Cc: Deepak S <deepak.s@xxxxxxxxxxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/i915_irq.c | 166 ++++++++++++-----------------------
> > drivers/gpu/drm/i915/i915_reg.h | 4 +-
> > drivers/gpu/drm/i915/intel_display.c | 2 +
> > drivers/gpu/drm/i915/intel_drv.h | 2 +
> > drivers/gpu/drm/i915/intel_pm.c | 13 +++
> > 5 files changed, 73 insertions(+), 114 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> > index 8e19d031c05d..2db5dbb87ced 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> <snip>
> > @@ -1433,14 +1376,14 @@ static void gen6_pm_rps_work(struct work_struct *work)
> >
> > mutex_lock(&dev_priv->rps.hw_lock);
> >
> > + pm_iir |= vlv_wa_c0_ei(dev_priv, pm_iir);
> > +
> > adj = dev_priv->rps.last_adj;
> > if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
> > if (adj > 0)
> > adj *= 2;
> > - else {
> > - /* CHV needs even encode values */
> > - adj = IS_CHERRYVIEW(dev_priv) ? 2 : 1;
> > - }
> > + else
> > + adj = 1;
> > new_delay = dev_priv->rps.cur_freq + adj;
> >
> > /*
> > @@ -1455,15 +1398,11 @@ static void gen6_pm_rps_work(struct work_struct *work)
> > else
> > new_delay = dev_priv->rps.min_freq_softlimit;
> > adj = 0;
> > - } else if (pm_iir & GEN6_PM_RP_UP_EI_EXPIRED) {
> > - new_delay = vlv_calc_delay_from_C0_counters(dev_priv);
> > } else if (pm_iir & GEN6_PM_RP_DOWN_THRESHOLD) {
> > if (adj < 0)
> > adj *= 2;
> > - else {
> > - /* CHV needs even encode values */
> > - adj = IS_CHERRYVIEW(dev_priv) ? -2 : -1;
> > - }
> > + else
> > + adj = -1;
> > new_delay = dev_priv->rps.cur_freq + adj;
> > } else { /* unknown event */
> > new_delay = dev_priv->rps.cur_freq;
> > @@ -1475,6 +1414,9 @@ static void gen6_pm_rps_work(struct work_struct *work)
> > new_delay = clamp_t(int, new_delay,
> > dev_priv->rps.min_freq_softlimit,
> > dev_priv->rps.max_freq_softlimit);
> > + /* CHV needs even encode values */
> > + if (IS_CHERRYVIEW(dev_priv))
> > + new_delay = new_delay & ~1;
>
> This will effectively make the first up interrupt a nop. The current
> code is the way it is precisely to avoid that. I guess it's not a huge
> problem but still seems silly to not satisfy the GPU when it wants moar
> speed.
Hmm, it's actually worse than that (see the last_adj). Ok, I should
split this out and tidy it up more carefully.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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