Re: [PATCH 2/4] drm/cma: add debugfs helpers

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Jan 08, 2013 at 10:08:44PM -0600, Rob Clark wrote:
> Add helper to display fb's which can be used directly in drm_info_list:
> 
> static struct drm_info_list foo_debugfs_list[] = {
> 		...
> 		{ "fb",   drm_fb_cma_debugfs_show, 0 },
> };
> 
> to display information about CMA fb objects, as well as a
> drm_gem_cma_describe() which can be used if the driver bothers to keep
> a list of CMA GEM objects.
> 
> Signed-off-by: Rob Clark <robdclark@gmail.com>
> ---
>  drivers/gpu/drm/drm_fb_cma_helper.c  | 53 ++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_gem_cma_helper.c | 21 ++++++++++++++
>  include/drm/drm_fb_cma_helper.h      |  5 ++++
>  include/drm/drm_gem_cma_helper.h     |  4 +++
>  4 files changed, 83 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
> index fd9d0af..18866ee 100644
> --- a/drivers/gpu/drm/drm_fb_cma_helper.c
> +++ b/drivers/gpu/drm/drm_fb_cma_helper.c
> @@ -180,6 +180,59 @@ struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
>  }
>  EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
>  
> +#ifdef CONFIG_DEBUG_FS
> +/**
> + * drm_fb_cma_describe() - Helper to dump information about a single
> + * CMA framebuffer object
> + */
> +void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m)
> +{
> +	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
> +	int i, n = drm_format_num_planes(fb->pixel_format);
> +
> +	seq_printf(m, "fb: %dx%d@%4.4s\n", fb->width, fb->height,
> +			(char *)&fb->pixel_format);
> +
> +	for (i = 0; i < n; i++) {
> +		seq_printf(m, "   %d: offset=%d pitch=%d, obj: ",
> +				i, fb->offsets[i], fb->pitches[i]);
> +		drm_gem_cma_describe(fb_cma->obj[i], m);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_cma_describe);
> +
> +/**
> + * drm_fb_cma_debugfs_show() - Helper to list CMA framebuffer objects
> + * in debugfs.
> + */
> +int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg)
> +{
> +	struct drm_info_node *node = (struct drm_info_node *) m->private;
> +	struct drm_device *dev = node->minor->dev;
> +	struct drm_framebuffer *fb;
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
> +	if (ret)
> +		return ret;
> +
> +	ret = mutex_lock_interruptible(&dev->struct_mutex);
> +	if (ret) {
> +		mutex_unlock(&dev->mode_config.mutex);
> +		return ret;
> +	}
> +
> +	list_for_each_entry(fb, &dev->mode_config.fb_list, head)
> +		drm_fb_cma_describe(fb, m);
> +
> +	mutex_unlock(&dev->struct_mutex);
> +	mutex_unlock(&dev->mode_config.mutex);

On top of my kms locking rework, this is way too much locking ;-) You
should get by with dev->mode_config.fb_lock to prevent the fbs from
disappearing. Everything else that drm_fb_cma_describe access should be
invariant already, so doesn't need any locking.
-DAniel

> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
> +#endif
> +
>  static struct fb_ops drm_fbdev_cma_ops = {
>  	.owner		= THIS_MODULE,
>  	.fb_fillrect	= sys_fillrect,
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 1aa8fee..0a7e011 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -249,3 +249,24 @@ int drm_gem_cma_dumb_destroy(struct drm_file *file_priv,
>  	return drm_gem_handle_delete(file_priv, handle);
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_destroy);
> +
> +#ifdef CONFIG_DEBUG_FS
> +void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m)
> +{
> +	struct drm_gem_object *obj = &cma_obj->base;
> +	struct drm_device *dev = obj->dev;
> +	uint64_t off = 0;
> +
> +	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> +
> +	if (obj->map_list.map)
> +		off = (uint64_t)obj->map_list.hash.key;
> +
> +	seq_printf(m, "%2d (%2d) %08llx %08Zx %p %d",
> +			obj->name, obj->refcount.refcount.counter,
> +			off, cma_obj->paddr, cma_obj->vaddr, obj->size);
> +
> +	seq_printf(m, "\n");
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
> +#endif
> diff --git a/include/drm/drm_fb_cma_helper.h b/include/drm/drm_fb_cma_helper.h
> index 76c7098..4a3fc24 100644
> --- a/include/drm/drm_fb_cma_helper.h
> +++ b/include/drm/drm_fb_cma_helper.h
> @@ -23,5 +23,10 @@ struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
>  struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
>  	unsigned int plane);
>  
> +#ifdef CONFIG_DEBUG_FS
> +void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m);
> +int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg);
> +#endif
> +
>  #endif
>  
> diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
> index f0f6b1a..63397ce 100644
> --- a/include/drm/drm_gem_cma_helper.h
> +++ b/include/drm/drm_gem_cma_helper.h
> @@ -41,4 +41,8 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
>  
>  extern const struct vm_operations_struct drm_gem_cma_vm_ops;
>  
> +#ifdef CONFIG_DEBUG_FS
> +void drm_gem_cma_describe(struct drm_gem_cma_object *obj, struct seq_file *m);
> +#endif
> +
>  #endif /* __DRM_GEM_CMA_HELPER_H__ */
> -- 
> 1.8.0.2
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch