On Fri, Jul 12, 2013 at 10:43:27PM +0200, Daniel Vetter wrote:
> The VECS enabling required some changes to how rps interrupts are
> enabled/disabled since VECS interrupts are handling with the PM
> interrupt registers.
>
> But now that the pre/postinstall sequences is identical for all
> platforms with rps support (snb, ivb, hsw, vlv) we can also use the
> exact same sequence to actually enable the rps interrupts. Strictly
> speaking using spinlocks is overkill on snb/ivb & vlv since they have
> no VECS ring, but imo that's more than made up by the common code.
>
> Hence this just unifies the vlv code with the snb-hsw code which
> matched exactly before the VECS enabling. See
>
> commit eda63ffb906c2fb3b609a0e87aeb63c0f25b9e6b
> Author: Ben Widawsky <ben at bwidawsk.net>
> Date: Tue May 28 19:22:26 2013 -0700
>
> drm/i915: Add PM regs to pre/post install
>
> and
>
> commit 4848405cced3b46f4ec7d404b8ed5873171ae10a
> Author: Ben Widawsky <ben at bwidawsk.net>
> Date: Tue May 28 19:22:27 2013 -0700
>
> drm/i915: make PM interrupt writes non-destructive
>
> for why the gen6 code (shared between snb, ivb and hsw) needed to be
> changed originally.
>
> v3: Improve the commit message to more clearly spell out why we want
> to unify the code and what exactly changes.
>
> Cc: Paulo Zanoni <przanoni at gmail.com>
> Cc: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> drivers/gpu/drm/i915/intel_pm.c | 59 ++++++++++++++++++++---------------------
> 1 file changed, 29 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index e609232..190ab96 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3121,13 +3121,10 @@ void valleyview_set_rps(struct drm_device *dev, u8 val)
> trace_intel_gpu_freq_change(vlv_gpu_freq(dev_priv->mem_freq, val));
> }
>
> -
> -static void gen6_disable_rps(struct drm_device *dev)
> +static void gen6_disable_rps_interrupts(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> - I915_WRITE(GEN6_RC_CONTROL, 0);
> - I915_WRITE(GEN6_RPNSWREQ, 1 << 31);
> I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
> I915_WRITE(GEN6_PMIER, I915_READ(GEN6_PMIER) & ~GEN6_PM_RPS_EVENTS);
I think actually, we need a POSTING_READ here before clearing
dev_priv->rps.pm_iir. Or maybe just one after disabling RPS is enough.
Not sure. Maybe just a hypothetical race.
> /* Complete PM interrupt masking here doesn't race with the rps work
> @@ -3142,23 +3139,23 @@ static void gen6_disable_rps(struct drm_device *dev)
> I915_WRITE(GEN6_PMIIR, GEN6_PM_RPS_EVENTS);
> }
>
> -static void valleyview_disable_rps(struct drm_device *dev)
> +static void gen6_disable_rps(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> I915_WRITE(GEN6_RC_CONTROL, 0);
> - I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
> - I915_WRITE(GEN6_PMIER, 0);
> - /* Complete PM interrupt masking here doesn't race with the rps work
> - * item again unmasking PM interrupts because that is using a different
> - * register (PMIMR) to mask PM interrupts. The only risk is in leaving
> - * stale bits in PMIIR and PMIMR which gen6_enable_rps will clean up. */
> + I915_WRITE(GEN6_RPNSWREQ, 1 << 31);
>
> - spin_lock_irq(&dev_priv->irq_lock);
> - dev_priv->rps.pm_iir = 0;
> - spin_unlock_irq(&dev_priv->irq_lock);
> + gen6_disable_rps_interrupts(dev);
> +}
> +
> +static void valleyview_disable_rps(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + I915_WRITE(GEN6_RC_CONTROL, 0);
>
> - I915_WRITE(GEN6_PMIIR, I915_READ(GEN6_PMIIR));
> + gen6_disable_rps_interrupts(dev);
>
> if (dev_priv->vlv_pctx) {
> drm_gem_object_unreference(&dev_priv->vlv_pctx->base);
> @@ -3191,6 +3188,21 @@ int intel_enable_rc6(const struct drm_device *dev)
> return (INTEL_RC6_ENABLE | INTEL_RC6p_ENABLE);
> }
>
> +static void gen6_enable_rps_interrupts(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + spin_lock_irq(&dev_priv->irq_lock);
> + /* FIXME: Our interrupt enabling sequence is bonghits.
> + * dev_priv->rps.pm_iir really should be 0 here. */
> + dev_priv->rps.pm_iir = 0;
> + I915_WRITE(GEN6_PMIMR, I915_READ(GEN6_PMIMR) & ~GEN6_PM_RPS_EVENTS);
I thought for enable, we want to modify PMIER? If it's not required, I
want a comment when not. Also, with your changes, it should be safe to
remove the FIXME if I am not mistaken.
> + I915_WRITE(GEN6_PMIIR, GEN6_PM_RPS_EVENTS);
> + spin_unlock_irq(&dev_priv->irq_lock);
> + /* unmask all PM interrupts */
> + I915_WRITE(GEN6_PMINTRMSK, 0);
> +}
> +
Also, maybe move this (with disable interrupts) to i915_irq.c?
> static void gen6_enable_rps(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -3319,15 +3331,7 @@ static void gen6_enable_rps(struct drm_device *dev)
>
> gen6_set_rps(dev_priv->dev, (gt_perf_status & 0xff00) >> 8);
>
> - spin_lock_irq(&dev_priv->irq_lock);
> - /* FIXME: Our interrupt enabling sequence is bonghits.
> - * dev_priv->rps.pm_iir really should be 0 here. */
> - dev_priv->rps.pm_iir = 0;
> - I915_WRITE(GEN6_PMIMR, I915_READ(GEN6_PMIMR) & ~GEN6_PM_RPS_EVENTS);
> - I915_WRITE(GEN6_PMIIR, GEN6_PM_RPS_EVENTS);
> - spin_unlock_irq(&dev_priv->irq_lock);
> - /* unmask all PM interrupts */
> - I915_WRITE(GEN6_PMINTRMSK, 0);
> + gen6_enable_rps_interrupts(dev);
>
> rc6vids = 0;
> ret = sandybridge_pcode_read(dev_priv, GEN6_PCODE_READ_RC6VIDS, &rc6vids);
> @@ -3597,12 +3601,7 @@ static void valleyview_enable_rps(struct drm_device *dev)
>
> valleyview_set_rps(dev_priv->dev, dev_priv->rps.rpe_delay);
>
> - spin_lock_irq(&dev_priv->irq_lock);
> - WARN_ON(dev_priv->rps.pm_iir != 0);
> - I915_WRITE(GEN6_PMIMR, 0);
> - spin_unlock_irq(&dev_priv->irq_lock);
> - /* enable all PM interrupts */
> - I915_WRITE(GEN6_PMINTRMSK, 0);
> + gen6_enable_rps_interrupts(dev);
>
> gen6_gt_force_wake_put(dev_priv);
> }
--
Ben Widawsky, Intel Open Source Technology Center
