On Thu, 9 Jan 2014 19:31:09 +0530
deepak.s@xxxxxxxxx wrote:
> From: Deepak S <deepak.s@xxxxxxxxx>
>
> When we enter RC6 and GFX Clocks are off, the voltage remains higher
> than Vmin. When we try to set the freq to RPe, it might fail since the
> Gfx clocks are down. So to fix this in Gfx idle, Bring the GFX clock up
> and set the freq to RPe then move GFx down.
>
> v2: remove vlv_update_rps_cur_delay function. Update commit message (Daniel)
>
> Signed-off-by: Deepak S <deepak.s@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 4 ++++
> drivers/gpu/drm/i915/intel_pm.c | 48 ++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index a699efd..e37831f 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4940,6 +4940,10 @@
> GEN6_PM_RP_DOWN_THRESHOLD | \
> GEN6_PM_RP_DOWN_TIMEOUT)
>
> +#define VLV_GTLC_SURVIVABILITY_REG 0x130098
> +#define VLV_GFX_CLK_STATUS_BIT (1<<3)
> +#define VLV_GFX_CLK_FORCE_ON_BIT (1<<2)
> +
> #define GEN6_GT_GFX_RC6_LOCKED 0x138104
> #define VLV_COUNTER_CONTROL 0x138104
> #define VLV_COUNT_RANGE_HIGH (1<<15)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 9c950e4..a8e05fe 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3050,6 +3050,51 @@ void gen6_set_rps(struct drm_device *dev, u8 val)
> trace_intel_gpu_freq_change(val * 50);
> }
>
> +/* vlv_set_rps_idle: Set the frequency to Rpe if Gfx clocks are down
> + *
> + * * If Gfx is Idle, then
> + * 1. Mask Turbo interrupts
> + * 2. Bring up Gfx clock
> + * 3. Change the freq to Rpe and wait till P-Unit updates freq
> + * 4. Clear the Force GFX CLK ON bit so that Gfx can down
> + * 5. Unmask Turbo interrupts
> +*/
> +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_delay == dev_priv->rps.rpe_delay)
> + return;
> +
> + /* Mask turbo interrupt so that they will not come in between */
> + I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
> +
> + /* Bring up the Gfx clock */
> + I915_WRITE(VLV_GTLC_SURVIVABILITY_REG,
> + I915_READ(VLV_GTLC_SURVIVABILITY_REG) |
> + VLV_GFX_CLK_FORCE_ON_BIT);
> +
> + if (wait_for_atomic(((VLV_GFX_CLK_STATUS_BIT &
> + I915_READ(VLV_GTLC_SURVIVABILITY_REG)) != 0), 500)) {
> + DRM_ERROR("GFX_CLK_ON request timed out\n");
> + return;
> + }
> +
> + valleyview_set_rps(dev_priv->dev, dev_priv->rps.rpe_delay);
> +
> + /* Release the Gfx clock */
> + I915_WRITE(VLV_GTLC_SURVIVABILITY_REG,
> + I915_READ(VLV_GTLC_SURVIVABILITY_REG) &
> + ~VLV_GFX_CLK_FORCE_ON_BIT);
> +
> + /* Unmask Turbo interrupts */
> + I915_WRITE(GEN6_PMINTRMSK, ~GEN6_PM_RPS_EVENTS);
> +}
> +
> +
> +
> void gen6_rps_idle(struct drm_i915_private *dev_priv)
> {
> struct drm_device *dev = dev_priv->dev;
> @@ -3057,7 +3102,7 @@ void gen6_rps_idle(struct drm_i915_private *dev_priv)
> mutex_lock(&dev_priv->rps.hw_lock);
> if (dev_priv->rps.enabled) {
> if (IS_VALLEYVIEW(dev))
> - valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
> + vlv_set_rps_idle(dev_priv);
> else
> gen6_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
> dev_priv->rps.last_adj = 0;
> @@ -4288,6 +4333,7 @@ void intel_gpu_ips_teardown(void)
> i915_mch_dev = NULL;
> spin_unlock_irq(&mchdev_lock);
> }
> +
> static void intel_init_emon(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
Yeah if we need to bring the gfx clocks up (which makes sense) then I
guess we need this. I'm not sure about the wait on the punit though;
that could end up penalizing us in bursty workloads, since the punit
can take quite some time to update the freq, but I don't actually see a
wait here?
Also, is the 500ms timeout really required for the gfx clock? That's a
long time to potentially hold the mutex and delay any clock boosting or
other activity...
--
Jesse Barnes, Intel Open Source Technology Center
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