[Intel-gfx] [PATCH 14/24] drm/i915: Add dev_priv->wm.mutex

[Paulo Zanoni]

2014-03-07 13:32 GMT-03:00  <ville.syrjala at linux.intel.com>:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Add a mutex to protect most of the watermark state. Will be useful when
> we start to update watermarks asynchronously from plane updates, or
> when we get finer grained locking for planes.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  | 11 ++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h |  5 ++++-
>  drivers/gpu/drm/i915/intel_pm.c  | 21 +++++++++++++++++++--
>  3 files changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 29da39f..0b19723 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1595,8 +1595,17 @@ typedef struct drm_i915_private {
>                 /* cursor */
>                 uint16_t cur_latency[5];
>
> -               /* current hardware state */
> +               /*
> +                * current hardware state
> +                * protected by dev_priv->wm.mutex
> +                */
>                 struct ilk_wm_values hw;
> +
> +               /*
> +                * protects some dev_priv->wm and intel_crtc->wm
> +                * state as well as the actual hardware registers
> +                */
> +               struct mutex mutex;
>         } wm;
>
>         struct i915_package_c8 pc8;
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index f022a78..8e32d69 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -384,7 +384,10 @@ struct intel_crtc {
>
>         /* per-pipe watermark state */
>         struct {
> -               /* watermarks currently being used  */
> +               /*
> +                * watermarks currently being used
> +                * protected by dev_priv->wm.mutex
> +                */
>                 struct intel_pipe_wm active;
>         } wm;
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 3f5c1dc..d8adcb3 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -2692,8 +2692,13 @@ static void ilk_write_wm_values(struct drm_i915_private *dev_priv,
>  static bool ilk_disable_lp_wm(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
> +       bool changed;
>
> -       return _ilk_disable_lp_wm(dev_priv, WM_DIRTY_LP_ALL);
> +       mutex_lock(&dev_priv->wm.mutex);
> +       changed = _ilk_disable_lp_wm(dev_priv, WM_DIRTY_LP_ALL);
> +       mutex_unlock(&dev_priv->wm.mutex);
> +
> +       return changed;
>  }
>
>  static void ilk_program_watermarks(struct drm_device *dev)
> @@ -2733,6 +2738,7 @@ static void ilk_update_wm(struct drm_crtc *crtc)
>  {
>         struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>         struct drm_device *dev = crtc->dev;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
>         struct ilk_pipe_wm_parameters params = {};
>         struct intel_pipe_wm pipe_wm = {};
>
> @@ -2740,12 +2746,17 @@ static void ilk_update_wm(struct drm_crtc *crtc)
>
>         intel_compute_pipe_wm(crtc, &params, &pipe_wm);
>
> +       mutex_lock(&dev_priv->wm.mutex);
> +
>         if (!memcmp(&intel_crtc->wm.active, &pipe_wm, sizeof(pipe_wm)))
> -               return;
> +               goto unlock;
>
>         intel_crtc->wm.active = pipe_wm;
>
>         ilk_program_watermarks(dev);
> +
> + unlock:
> +       mutex_unlock(&dev_priv->wm.mutex);
>  }
>
>  static void ilk_update_sprite_wm(struct drm_plane *plane,
> @@ -2817,10 +2828,14 @@ void ilk_wm_get_hw_state(struct drm_device *dev)
>         struct drm_i915_private *dev_priv = dev->dev_private;
>         struct drm_crtc *crtc;
>
> +       mutex_lock(&dev_priv->wm.mutex);
> +
>         _ilk_wm_get_hw_state(dev, &dev_priv->wm.hw);
>
>         list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
>                 _ilk_pipe_wm_hw_to_sw(crtc);
> +
> +       mutex_unlock(&dev_priv->wm.mutex);
>  }
>
>  /**
> @@ -5760,6 +5775,8 @@ void intel_init_pm(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
>
> +       mutex_init(&dev_priv->wm.mutex);
> +

I think you should probably init this at intel_pm_setup(), which is
called way earlier. Just to be safe.

With that fixed: Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>.

>         if (HAS_FBC(dev)) {
>                 if (INTEL_INFO(dev)->gen >= 7) {
>                         dev_priv->display.fbc_enabled = ironlake_fbc_enabled;
> --
> 1.8.3.2
>
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-- 
Paulo Zanoni