[Intel-gfx] [PATCH v3 2/4] drm/i915: use power get/put instead of set for power on after init

Paulo Zanoni przanoni at gmail.com
Fri Oct 25 21:31:09 CEST 2013


2013/10/25 Imre Deak <imre.deak at intel.com>:
> Currently we make sure that all power domains are enabled during driver
> init and turn off unneded ones only after the first modeset. Similarly
> during suspend we enable all power domains, which will remain on through
> the following resume until the first modeset.
>
> This logic is supported by intel_set_power_well() in the power domain
> framework. It would be nice to simplify the API, so that we only have
> get/put functions and make it more explicit on the higher level how this
> "power well on during init" logic works. This will make it also easier
> if in the future we want to shorten the time the power wells are on.
>
> For this add a new device private flag tracking whether we have the
> power wells on because of init/suspend and use only
> intel_display_power_get()/put(). As nothing else uses
> intel_set_power_well() we can remove it.
>
> This also fixes
>
> commit 6efdf354ddb186c6604d1692075421e8d2c740e9
> Author: Imre Deak <imre.deak at intel.com>
> Date:   Wed Oct 16 17:25:52 2013 +0300
>
>     drm/i915: enable only the needed power domains during modeset
>
> where removing intel_set_power_well() resulted in not releasing the
> reference on the power well that was taken during init and thus leaving
> the power well on all the time. Regression reported by Paulo.
>
> v2:
> - move the init_power_on flag to the power_domains struct (Daniel)
>
> v3:
> - add note about this being a regression fix too (Paulo)

I didn't closely follow the first 5 patches, but this one makes sense.

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

>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c      |  2 +-
>  drivers/gpu/drm/i915/i915_drv.c      |  2 +-
>  drivers/gpu/drm/i915/i915_drv.h      |  8 +++++++-
>  drivers/gpu/drm/i915/intel_display.c | 17 +++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h     |  1 +
>  drivers/gpu/drm/i915/intel_pm.c      | 37 +-----------------------------------
>  6 files changed, 28 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index fd848ef..b722b35 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1710,7 +1710,7 @@ int i915_driver_unload(struct drm_device *dev)
>                 /* The i915.ko module is still not prepared to be loaded when
>                  * the power well is not enabled, so just enable it in case
>                  * we're going to unload/reload. */
> -               intel_set_power_well(dev, true);
> +               intel_display_set_init_power(dev, true);
>                 i915_remove_power_well(dev);
>         }
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 85ae0dc..770c9f8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -477,7 +477,7 @@ static int i915_drm_freeze(struct drm_device *dev)
>         /* We do a lot of poking in a lot of registers, make sure they work
>          * properly. */
>         hsw_disable_package_c8(dev_priv);
> -       intel_set_power_well(dev, true);
> +       intel_display_set_init_power(dev, true);
>
>         drm_kms_helper_poll_disable(dev);
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7315095..3565db2 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -100,6 +100,7 @@ enum intel_display_power_domain {
>         POWER_DOMAIN_TRANSCODER_C,
>         POWER_DOMAIN_TRANSCODER_EDP,
>         POWER_DOMAIN_VGA,
> +       POWER_DOMAIN_INIT,
>
>         POWER_DOMAIN_NUM,
>  };
> @@ -913,12 +914,17 @@ struct i915_power_well {
>         struct drm_device *device;
>         /* power well enable/disable usage count */
>         int count;
> -       int i915_request;
>  };
>
>  #define I915_MAX_POWER_WELLS 1
>
>  struct i915_power_domains {
> +       /*
> +        * Power wells needed for initialization at driver init and suspend
> +        * time are on. They are kept on until after the first modeset.
> +        */
> +       bool init_power_on;
> +
>         struct mutex lock;
>         struct i915_power_well power_wells[I915_MAX_POWER_WELLS];
>  };
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 3e79a2a..0c2e83c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6573,6 +6573,21 @@ static unsigned long get_pipe_power_domains(struct drm_device *dev,
>         return mask;
>  }
>
> +void intel_display_set_init_power(struct drm_device *dev, bool enable)
> +{
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +       if (dev_priv->power_domains.init_power_on == enable)
> +               return;
> +
> +       if (enable)
> +               intel_display_power_get(dev, POWER_DOMAIN_INIT);
> +       else
> +               intel_display_power_put(dev, POWER_DOMAIN_INIT);
> +
> +       dev_priv->power_domains.init_power_on = enable;
> +}
> +
>  static void modeset_update_power_wells(struct drm_device *dev)
>  {
>         unsigned long pipe_domains[I915_MAX_PIPES] = { 0, };
> @@ -6604,6 +6619,8 @@ static void modeset_update_power_wells(struct drm_device *dev)
>
>                 crtc->enabled_power_domains = pipe_domains[crtc->pipe];
>         }
> +
> +       intel_display_set_init_power(dev, false);
>  }
>
>  static void haswell_modeset_global_resources(struct drm_device *dev)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index af1553c..bf4394a 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -692,6 +692,7 @@ bool intel_crtc_active(struct drm_crtc *crtc);
>  void i915_disable_vga_mem(struct drm_device *dev);
>  void hsw_enable_ips(struct intel_crtc *crtc);
>  void hsw_disable_ips(struct intel_crtc *crtc);
> +void intel_display_set_init_power(struct drm_device *dev, bool enable);
>
>
>  /* intel_dp.c */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 09ca6f9..4c38e28 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5706,41 +5706,6 @@ void i915_remove_power_well(struct drm_device *dev)
>         hsw_pwr = NULL;
>  }
>
> -void intel_set_power_well(struct drm_device *dev, bool enable)
> -{
> -       struct drm_i915_private *dev_priv = dev->dev_private;
> -       struct i915_power_domains *power_domains = &dev_priv->power_domains;
> -       struct i915_power_well *power_well;
> -
> -       if (!HAS_POWER_WELL(dev))
> -               return;
> -
> -       if (!i915_disable_power_well && !enable)
> -               return;
> -
> -       mutex_lock(&power_domains->lock);
> -
> -       power_well = &power_domains->power_wells[0];
> -       /*
> -        * This function will only ever contribute one
> -        * to the power well reference count. i915_request
> -        * is what tracks whether we have or have not
> -        * added the one to the reference count.
> -        */
> -       if (power_well->i915_request == enable)
> -               goto out;
> -
> -       power_well->i915_request = enable;
> -
> -       if (enable)
> -               __intel_power_well_get(power_well);
> -       else
> -               __intel_power_well_put(power_well);
> -
> - out:
> -       mutex_unlock(&power_domains->lock);
> -}
> -
>  static void intel_resume_power_well(struct drm_device *dev)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -5772,7 +5737,7 @@ void intel_init_power_well(struct drm_device *dev)
>                 return;
>
>         /* For now, we need the power well to be always enabled. */
> -       intel_set_power_well(dev, true);
> +       intel_display_set_init_power(dev, true);
>         intel_resume_power_well(dev);
>
>         /* We're taking over the BIOS, so clear any requests made by it since
> --
> 1.8.4
>
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-- 
Paulo Zanoni



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