[Intel-gfx] [RFC] [PATCH] drm/i915: Require HW contexts (when possible)

Ville Syrjälä ville.syrjala at linux.intel.com
Thu Oct 17 19:52:17 CEST 2013


On Thu, Oct 17, 2013 at 09:59:43AM -0700, Ben Widawsky wrote:
> From: Ben Widawsky <benjamin.widawsky at intel.com>
> 
> Only compile tested
> 
> CC: Kenneth Graunke <kenneth at whitecape.org>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_drv.c         |  5 +---
>  drivers/gpu/drm/i915/i915_drv.h         |  3 +--
>  drivers/gpu/drm/i915/i915_gem.c         |  7 +++++-
>  drivers/gpu/drm/i915/i915_gem_context.c | 43 +++++++++++++++------------------
>  drivers/gpu/drm/i915/i915_sysfs.c       |  6 ++---
>  5 files changed, 31 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 1060a96..8c90559 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -750,14 +750,11 @@ int i915_reset(struct drm_device *dev)
>  	 */
>  	if (drm_core_check_feature(dev, DRIVER_MODESET) ||
>  			!dev_priv->ums.mm_suspended) {
> -		bool hw_contexts_disabled = dev_priv->hw_contexts_disabled;
>  		dev_priv->ums.mm_suspended = 0;
>  
>  		ret = i915_gem_init_hw(dev);
> -		if (!hw_contexts_disabled && dev_priv->hw_contexts_disabled)
> -			DRM_ERROR("HW contexts didn't survive reset\n");
> -		mutex_unlock(&dev->struct_mutex);
>  		if (ret) {
> +			mutex_unlock(&dev->struct_mutex);

Botched locking.

>  			DRM_ERROR("Failed hw init on reset %d\n", ret);
>  			return ret;
>  		}
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index e4ff8e9..21b2c37 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1411,7 +1411,6 @@ typedef struct drm_i915_private {
>  	struct drm_property *broadcast_rgb_property;
>  	struct drm_property *force_audio_property;
>  
> -	bool hw_contexts_disabled;
>  	uint32_t hw_context_size;
>  	struct list_head context_list;
>  
> @@ -2140,7 +2139,7 @@ i915_gem_obj_ggtt_pin(struct drm_i915_gem_object *obj,
>  }
>  
>  /* i915_gem_context.c */
> -void i915_gem_context_init(struct drm_device *dev);
> +int __must_check i915_gem_context_init(struct drm_device *dev);
>  void i915_gem_context_fini(struct drm_device *dev);
>  void i915_gem_context_close(struct drm_device *dev, struct drm_file *file);
>  int i915_switch_context(struct intel_ring_buffer *ring,
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 34df59b..0df40e6 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4463,7 +4463,12 @@ i915_gem_init_hw(struct drm_device *dev)
>  	 * XXX: There was some w/a described somewhere suggesting loading
>  	 * contexts before PPGTT.
>  	 */
> -	i915_gem_context_init(dev);
> +	ret = i915_gem_context_init(dev);
> +	if (ret) {

i915_gem_cleanup_ringbuffer() ?

Damn our error unwinding is hard to follow, which means it's probably
broken somewhere. From i915_load_modeset_init() we call
i915_gem_init() which does some stuff directly and then calls
i915_gem_init_hw(). And if we get some error later in i915_load_modeset_init(),
we manually unwind all the stuff that i915_gem_init() and i915_gem_init_hw()
supposedly did. This could sure use some i915_gem_fini() and i915_gem_fini_hw()
to keep the do+undo code close together.

> +		DRM_ERROR("Context initialization failed %d\n", ret);
> +		return ret;
> +	}
> +
>  	if (dev_priv->mm.aliasing_ppgtt) {
>  		ret = dev_priv->mm.aliasing_ppgtt->enable(dev);
>  		if (ret) {
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index cc619c1..4625670 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -244,36 +244,34 @@ err_destroy:
>  	return ret;
>  }
>  
> -void i915_gem_context_init(struct drm_device *dev)
> +int i915_gem_context_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	int ret;
>  
> -	if (!HAS_HW_CONTEXTS(dev)) {
> -		dev_priv->hw_contexts_disabled = true;
> -		DRM_DEBUG_DRIVER("Disabling HW Contexts; old hardware\n");
> -		return;
> -	}
> +	if (!HAS_HW_CONTEXTS(dev))
> +		return 0;
>  
>  	/* If called from reset, or thaw... we've been here already */
> -	if (dev_priv->hw_contexts_disabled ||
> -	    dev_priv->ring[RCS].default_context)
> -		return;
> +	if (dev_priv->ring[RCS].default_context)
> +		return 0;
>  
>  	dev_priv->hw_context_size = round_up(get_context_size(dev), 4096);
>  
>  	if (dev_priv->hw_context_size > (1<<20)) {
> -		dev_priv->hw_contexts_disabled = true;
>  		DRM_DEBUG_DRIVER("Disabling HW Contexts; invalid size\n");
> -		return;
> +		return -E2BIG;
>  	}
>  
> -	if (create_default_context(dev_priv)) {
> -		dev_priv->hw_contexts_disabled = true;
> -		DRM_DEBUG_DRIVER("Disabling HW Contexts; create failed\n");
> -		return;
> +	ret = create_default_context(dev_priv);
> +	if (ret) {
> +		DRM_DEBUG_DRIVER("Disabling HW Contexts; create failed %d\n",
> +				 ret);
> +		return ret;
>  	}
>  
>  	DRM_DEBUG_DRIVER("HW context support initialized\n");
> +	return 0;
>  }
>  
>  void i915_gem_context_fini(struct drm_device *dev)
> @@ -281,7 +279,7 @@ void i915_gem_context_fini(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct i915_hw_context *dctx = dev_priv->ring[RCS].default_context;
>  
> -	if (dev_priv->hw_contexts_disabled)
> +	if (!HAS_HW_CONTEXTS(dev))
>  		return;
>  
>  	/* The only known way to stop the gpu from accessing the hw context is
> @@ -324,16 +322,16 @@ i915_gem_context_get_hang_stats(struct drm_device *dev,
>  				struct drm_file *file,
>  				u32 id)
>  {
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_i915_file_private *file_priv = file->driver_priv;
>  	struct i915_hw_context *ctx;
>  
>  	if (id == DEFAULT_CONTEXT_ID)
>  		return &file_priv->hang_stats;
>  
> -	ctx = NULL;
> -	if (!dev_priv->hw_contexts_disabled)
> -		ctx = i915_gem_context_get(file->driver_priv, id);
> +	if (!HAS_HW_CONTEXTS(dev))
> +		return ERR_PTR(-ENOENT);
> +
> +	ctx = i915_gem_context_get(file->driver_priv, id);
>  	if (ctx == NULL)
>  		return ERR_PTR(-ENOENT);
>  
> @@ -506,7 +504,7 @@ int i915_switch_context(struct intel_ring_buffer *ring,
>  	struct drm_i915_private *dev_priv = ring->dev->dev_private;
>  	struct i915_hw_context *to;
>  
> -	if (dev_priv->hw_contexts_disabled)
> +	if (!HAS_HW_CONTEXTS(ring->dev))
>  		return 0;
>  
>  	WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
> @@ -531,7 +529,6 @@ int i915_switch_context(struct intel_ring_buffer *ring,
>  int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
>  				  struct drm_file *file)
>  {
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_i915_gem_context_create *args = data;
>  	struct drm_i915_file_private *file_priv = file->driver_priv;
>  	struct i915_hw_context *ctx;
> @@ -540,7 +537,7 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
>  	if (!(dev->driver->driver_features & DRIVER_GEM))
>  		return -ENODEV;
>  
> -	if (dev_priv->hw_contexts_disabled)
> +	if (!HAS_HW_CONTEXTS(dev))
>  		return -ENODEV;
>  
>  	ret = i915_mutex_lock_interruptible(dev);
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> index bb31ff3..47bc51b 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -183,13 +183,13 @@ i915_l3_write(struct file *filp, struct kobject *kobj,
>  	int slice = (int)(uintptr_t)attr->private;
>  	int ret;
>  
> +	if (!HAS_HW_CONTEXTS(drm_dev))
> +		return -ENXIO;
> +
>  	ret = l3_access_valid(drm_dev, offset);
>  	if (ret)
>  		return ret;
>  
> -	if (dev_priv->hw_contexts_disabled)
> -		return -ENXIO;
> -
>  	ret = i915_mutex_lock_interruptible(drm_dev);
>  	if (ret)
>  		return ret;
> -- 
> 1.8.4.1
> 
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-- 
Ville Syrjälä
Intel OTC



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