Re: [PATCH 3/3] drm/i915: Move the fbdev async_schedule() into intel_fbdev.c

[Lukas Wunner <lukas@wunner.de>]

Hi Ville,

On Fri, Nov 06, 2015 at 03:08:33PM +0200, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Reading the driver load/unload code leaves one confused as there's
> an async_schedule() in the load, but not async_synchronize_full()
> in sight. In fact it's hidden inside intel_fbdev.c. So let's move the
> async_schedule() into intel_fbdev.c as well so that it's next to the
> async_synchronize_full(), which should make the relationship easier
> to see.

Hm, what do you think about solving it the other way round, i.e. moving
the async_synchronize_full() to i915_driver_unload()? Incidentally I was
working on this same part of the code and that's how I solved it. This way
it's possible to call intel_fbdev_fini() from intel_fbdev_initial_config().
With your solution this would deadlock.

Link: https://github.com/l1k/linux/commit/aa12badac846
Message-Id: <aa12badac846f24b49d83768146b62e2ac159eb3.1446987413.git.lukas@wunner.de>

Thanks,

Lukas


> Plus this way we won't schedule a nop function call when fbdev is
> disabled. And we were passing a pointer to a static inline
> function to async_schedule(), which seems rather dubious to me.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c    | 3 +--
>  drivers/gpu/drm/i915/intel_drv.h   | 4 ++--
>  drivers/gpu/drm/i915/intel_fbdev.c | 7 ++++++-
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index c58048f..cae3d78 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -28,7 +28,6 @@
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> -#include <linux/async.h>
>  #include <drm/drmP.h>
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_fb_helper.h>
> @@ -437,7 +436,7 @@ static int i915_load_modeset_init(struct drm_device *dev)
>  	 * scanning against hotplug events. Hence do this first and ignore the
>  	 * tiny window where we will loose hotplug notifactions.
>  	 */
> -	async_schedule(intel_fbdev_initial_config, dev_priv);
> +	intel_fbdev_initial_config_async(dev);
>  
>  	drm_kms_helper_poll_init(dev);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 00d9882..50c78b6 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1298,7 +1298,7 @@ void intel_dvo_init(struct drm_device *dev);
>  /* legacy fbdev emulation in intel_fbdev.c */
>  #ifdef CONFIG_DRM_FBDEV_EMULATION
>  extern int intel_fbdev_init(struct drm_device *dev);
> -extern void intel_fbdev_initial_config(void *data, async_cookie_t cookie);
> +extern void intel_fbdev_initial_config_async(struct drm_device *dev);
>  extern void intel_fbdev_fini(struct drm_device *dev);
>  extern void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous);
>  extern void intel_fbdev_output_poll_changed(struct drm_device *dev);
> @@ -1309,7 +1309,7 @@ static inline int intel_fbdev_init(struct drm_device *dev)
>  	return 0;
>  }
>  
> -static inline void intel_fbdev_initial_config(void *data, async_cookie_t cookie)
> +static inline void intel_fbdev_initial_config_async(struct drm_device *dev)
>  {
>  }
>  
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 840d6bf..fe1fdb6 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -702,7 +702,7 @@ int intel_fbdev_init(struct drm_device *dev)
>  	return 0;
>  }
>  
> -void intel_fbdev_initial_config(void *data, async_cookie_t cookie)
> +static void intel_fbdev_initial_config(void *data, async_cookie_t cookie)
>  {
>  	struct drm_i915_private *dev_priv = data;
>  	struct intel_fbdev *ifbdev = dev_priv->fbdev;
> @@ -711,6 +711,11 @@ void intel_fbdev_initial_config(void *data, async_cookie_t cookie)
>  	drm_fb_helper_initial_config(&ifbdev->helper, ifbdev->preferred_bpp);
>  }
>  
> +void intel_fbdev_initial_config_async(struct drm_device *dev)
> +{
> +	async_schedule(intel_fbdev_initial_config, to_i915(dev));
> +}
> +
>  void intel_fbdev_fini(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> -- 
> 2.4.10
> 
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