Re: [PATCH 1/7] drm/i915: Relax RPS contraints to allows setting minfreq on idle

Deepak S
2015-03-18T05:47:39Z

On Friday 06 March 2015 08:36 PM, Chris Wilson wrote:
> When we idle, we set the GPU frequency to the hardware minimum (not user
> minimum). We introduce a new variable to distinguish between the
> different roles, and to allow easy tuning of the idle frequency without
> impacting over aspects of RPS. Setting the minimum frequency should be a
> safety blanket as the pcu on the GPU should be power gating itself
> anyway. However, in order for us to do set the absolute minimum
> frequency, we need to relax a few of our assertions that we do not
> exceed the user limits.
>
> v2: Add idle_freq
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 6 ++++++
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/intel_pm.c | 35 +++++++++++++++++++----------------
> 3 files changed, 26 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index c3a5322bc7f4..cc83cc0ff823 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1219,6 +1219,9 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>
> seq_printf(m, "Max overclocked frequency: %dMHz\n",
> intel_gpu_freq(dev_priv, dev_priv->rps.max_freq));
> +
> + seq_printf(m, "Idle freq: %d MHz\n",
> + intel_gpu_freq(dev_priv, dev_priv->rps.idle_freq));
> } else if (IS_VALLEYVIEW(dev)) {
> u32 freq_sts;
>
> @@ -1233,6 +1236,9 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
> seq_printf(m, "min GPU freq: %d MHz\n",
> intel_gpu_freq(dev_priv, dev_priv->rps.min_freq));
>
> + seq_printf(m, "idle GPU freq: %d MHz\n",
> + intel_gpu_freq(dev_priv, dev_priv->rps.idle_freq));
> +
> seq_printf(m,
> "efficient (RPe) frequency: %d MHz\n",
> intel_gpu_freq(dev_priv, dev_priv->rps.efficient_freq));
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 18a6e56c7c94..73292a183492 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1022,6 +1022,7 @@ struct intel_gen6_power_mgmt {
> u8 max_freq_softlimit; /* Max frequency permitted by the driver */
> u8 max_freq; /* Maximum frequency, RP0 if not overclocking */
> u8 min_freq; /* AKA RPn. Minimum frequency */
> + u8 idle_freq; /* Frequency to request when we are idle */
> u8 efficient_freq; /* AKA RPe. Pre-determined balanced frequency */
> u8 rp1_freq; /* "less than" RP0 power/freqency */
> u8 rp0_freq; /* Non-overclocked max frequency. */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 6b277f9f7ffa..e53724516852 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3711,9 +3711,9 @@ static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
> break;
> }
> /* Max/min bins are special */
> - if (val == dev_priv->rps.min_freq_softlimit)
> + if (val <= dev_priv->rps.min_freq_softlimit)
> new_power = LOW_POWER;
> - if (val == dev_priv->rps.max_freq_softlimit)
> + if (val >= dev_priv->rps.max_freq_softlimit)
> new_power = HIGH_POWER;
> if (new_power == dev_priv->rps.power)
> return;
> @@ -3802,8 +3802,8 @@ static void gen6_set_rps(struct drm_device *dev, u8 val)
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
> - WARN_ON(val > dev_priv->rps.max_freq_softlimit);
> - WARN_ON(val < dev_priv->rps.min_freq_softlimit);
> + WARN_ON(val > dev_priv->rps.max_freq);
> + WARN_ON(val < dev_priv->rps.min_freq);
>
> /* min/max delay may still have been modified so be sure to
> * write the limits value.
> @@ -3836,8 +3836,8 @@ static void valleyview_set_rps(struct drm_device *dev, u8 val)
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
> - WARN_ON(val > dev_priv->rps.max_freq_softlimit);
> - WARN_ON(val < dev_priv->rps.min_freq_softlimit);
> + WARN_ON(val > dev_priv->rps.max_freq);
> + WARN_ON(val < dev_priv->rps.min_freq);
>
> if (WARN_ONCE(IS_CHERRYVIEW(dev) && (val & 1),
> "Odd GPU freq value\n"))
> @@ -3864,10 +3864,11 @@ static void valleyview_set_rps(struct drm_device *dev, u8 val)
> static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
> {
> struct drm_device *dev = dev_priv->dev;
> + u32 val = dev_priv->rps.idle_freq;
>
> /* CHV and latest VLV don't need to force the gfx clock */
> if (IS_CHERRYVIEW(dev) || dev->pdev->revision >= 0xd) {
> - valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
> + valleyview_set_rps(dev_priv->dev, val);
> return;
> }
>
> @@ -3875,7 +3876,7 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
> * When we are idle. Drop to min voltage state.
> */
>
> - if (dev_priv->rps.cur_freq <= dev_priv->rps.min_freq_softlimit)
> + if (dev_priv->rps.cur_freq <= val)
> return;
>
> /* Mask turbo interrupt so that they will not come in between */
> @@ -3884,10 +3885,9 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
>
> vlv_force_gfx_clock(dev_priv, true);
>
> - dev_priv->rps.cur_freq = dev_priv->rps.min_freq_softlimit;
> + dev_priv->rps.cur_freq = val;
>
> - vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ,
> - dev_priv->rps.min_freq_softlimit);
> + vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ, val);
>
> if (wait_for(((vlv_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS))
> & GENFREQSTATUS) == 0, 100))
> @@ -3895,8 +3895,7 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
>
> vlv_force_gfx_clock(dev_priv, false);
>
> - I915_WRITE(GEN6_PMINTRMSK,
> - gen6_rps_pm_mask(dev_priv, dev_priv->rps.cur_freq));
> + I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));
> }
>
> void gen6_rps_idle(struct drm_i915_private *dev_priv)
> @@ -3908,7 +3907,7 @@ void gen6_rps_idle(struct drm_i915_private *dev_priv)
> if (IS_VALLEYVIEW(dev))
> vlv_set_rps_idle(dev_priv);
> else
> - gen6_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
> + gen6_set_rps(dev_priv->dev, dev_priv->rps.idle_freq);
> dev_priv->rps.last_adj = 0;
> }
> mutex_unlock(&dev_priv->rps.hw_lock);
> @@ -4059,6 +4058,8 @@ static void gen6_init_rps_frequencies(struct drm_device *dev)
> dev_priv->rps.max_freq);
> }
>
> + dev_priv->rps.idle_freq = dev_priv->rps.min_freq;
> +
> /* Preserve min/max settings in case of re-init */
> if (dev_priv->rps.max_freq_softlimit == 0)
> dev_priv->rps.max_freq_softlimit = dev_priv->rps.max_freq;
> @@ -4227,7 +4228,7 @@ static void gen8_enable_rps(struct drm_device *dev)
> /* 6: Ring frequency + overclocking (our driver does this later */
>
> dev_priv->rps.power = HIGH_POWER; /* force a reset */
> - gen6_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
> + gen6_set_rps(dev_priv->dev, dev_priv->rps.idle_freq);
>
> intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
> }
> @@ -4321,7 +4322,7 @@ static void gen6_enable_rps(struct drm_device *dev)
> }
>
> dev_priv->rps.power = HIGH_POWER; /* force a reset */
> - gen6_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
> + gen6_set_rps(dev_priv->dev, dev_priv->rps.idle_freq);
>
> rc6vids = 0;
> ret = sandybridge_pcode_read(dev_priv, GEN6_PCODE_READ_RC6VIDS, &rc6vids);
> @@ -4761,6 +4762,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)

I think we missed initializing idle_freq in valleyview init platform?

> dev_priv->rps.min_freq) & 1,
> "Odd GPU freq values\n");
>
> + dev_priv->rps.idle_freq = dev_priv->rps.min_freq;
> +
> /* Preserve min/max settings in case of re-init */
> if (dev_priv->rps.max_freq_softlimit == 0)
> dev_priv->rps.max_freq_softlimit = dev_priv->rps.max_freq;