[Intel-gfx] [PATCH 1/8] drm/i915: Rebalance runtime pm vs forcewake

[Paulo Zanoni]

2014-12-08 16:27 GMT-02:00 Mika Kuoppala <mika.kuoppala at linux.intel.com>:
> From: Chris Wilson <chris at chris-wilson.co.uk>
>
> Calling intel_runtime_pm_put() is illegal from a soft-irq context, so
> revert the crude hack
>
> commit aa0b3b5bb8768c1a6a6788869d9c7015eae7e80c
> Author: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Date:   Tue Apr 1 14:55:07 2014 -0300
>
>     drm/i915: don't schedule force_wake_timer at gen6_read
>
> and apply the single line corrective instead.
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=80913
> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

This patch adds tons and tons of new WARNs when running
igt/tests/pm_rpm on BDW, including:

WARNING: CPU: 1 PID: 228 at drivers/gpu/drm/i915/intel_uncore.c:623
assert_force_wake_inactive+0x36/0x40 [i915]()
WARN_ON(dev_priv->uncore.forcewake_count > 0)


> ---
>  drivers/gpu/drm/i915/i915_drv.c     |  1 +
>  drivers/gpu/drm/i915/intel_uncore.c | 18 ++++++------------
>  2 files changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 71be3c9..706b122 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1402,6 +1402,7 @@ static int intel_runtime_suspend(struct device *device)
>         }
>
>         del_timer_sync(&dev_priv->gpu_error.hangcheck_timer);
> +       intel_uncore_forcewake_reset(dev, false);
>         dev_priv->pm.suspended = true;
>
>         /*
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 46de8d7..38ac389 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -449,8 +449,6 @@ static void gen6_force_wake_timer(unsigned long arg)
>         if (--dev_priv->uncore.forcewake_count == 0)
>                 dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
>         spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
> -
> -       intel_runtime_pm_put(dev_priv);
>  }
>
>  void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
> @@ -586,7 +584,6 @@ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine)
>  void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
>  {
>         unsigned long irqflags;
> -       bool delayed = false;
>
>         if (!dev_priv->uncore.funcs.force_wake_put)
>                 return;
> @@ -603,21 +600,19 @@ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine)
>                 goto out;
>         }
>
> -
>         spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
>         WARN_ON(!dev_priv->uncore.forcewake_count);
>
>         if (--dev_priv->uncore.forcewake_count == 0) {
>                 dev_priv->uncore.forcewake_count++;
> -               delayed = true;
>                 mod_timer_pinned(&dev_priv->uncore.force_wake_timer,
>                                  jiffies + 1);
>         }
> +
>         spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
>
>  out:
> -       if (!delayed)
> -               intel_runtime_pm_put(dev_priv);
> +       intel_runtime_pm_put(dev_priv);
>  }
>
>  void assert_force_wake_inactive(struct drm_i915_private *dev_priv)
> @@ -777,12 +772,11 @@ gen6_read##x(struct drm_i915_private *dev_priv, off_t reg, bool trace) { \
>             NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
>                 dev_priv->uncore.funcs.force_wake_get(dev_priv, \
>                                                       FORCEWAKE_ALL); \
> -               val = __raw_i915_read##x(dev_priv, reg); \
> -               dev_priv->uncore.funcs.force_wake_put(dev_priv, \
> -                                                     FORCEWAKE_ALL); \
> -       } else { \
> -               val = __raw_i915_read##x(dev_priv, reg); \
> +               dev_priv->uncore.forcewake_count++; \
> +               mod_timer_pinned(&dev_priv->uncore.force_wake_timer, \
> +                                jiffies + 1); \
>         } \
> +       val = __raw_i915_read##x(dev_priv, reg); \
>         hsw_unclaimed_reg_debug(dev_priv, reg, true, false); \
>         REG_READ_FOOTER; \
>  }
> --
> 1.9.1
>
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-- 
Paulo Zanoni