[PATCH v2 5/8] drm/gem-fb-helper: Add drm_gem_fb_debugfs_show()

Noralf Trønnes noralf at tronnes.org
Wed Oct 18 19:44:22 UTC 2017


Den 17.10.2017 14.56, skrev Daniel Vetter:
> On Sun, Oct 15, 2017 at 06:30:39PM +0200, Noralf Trønnes wrote:
>> Add drm_gem_fb_debugfs_show() function to provide a debugfs
>> representation of the framebuffer and GEM object(s).
>>
>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
>> ---
>>   drivers/gpu/drm/drm_gem_framebuffer_helper.c | 45 ++++++++++++++++++++++++++++
>>   include/drm/drm_gem_framebuffer_helper.h     |  6 ++++
>>   2 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
>> index aa8cb9bfa499..18fdcc29427a 100644
>> --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
>> @@ -265,6 +265,51 @@ int drm_gem_fb_prepare_fb(struct drm_plane *plane,
>>   }
>>   EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
>>   
>> +#ifdef CONFIG_DEBUG_FS
>> +static void drm_gem_fb_describe(struct drm_framebuffer *fb, struct seq_file *m)
>> +{
>> +	struct drm_gem_object *obj;
>> +	unsigned int i;
>> +
>> +	seq_printf(m, "[FB:%d] %dx%d@%4.4s\n", fb->base.id, fb->width,
>> +		   fb->height, (char *)&fb->format->format);
>> +
>> +	for (i = 0; i < fb->format->num_planes; i++) {
>> +		obj = fb->obj[i];
>> +		seq_printf(m, "\t%u: offset=%d pitch=%d, GEM: name=%d",
>> +			   i, fb->offsets[i], fb->pitches[i], obj->name);
>> +		seq_printf(m, " refcount=%d start=%08lx size=%zu%s\n",
>> +			   kref_read(&obj->refcount),
>> +			   drm_vma_node_start(&obj->vma_node), obj->size,
>> +			   obj->import_attach ? " (imported)" : "");
>> +	}
>> +}
> Given that gem is the defacto standard and that we can easily skip the gem
> specific stuff on non-gem drivers by checking the pointer for NULL I think
> we should add the framebuffer list by default. Like we already do for e.g.
> atomic state, see drm_atomic_debugfs_init. Probably better to split it up
> into a generic fb describe, which calls into a gem_obj describe, with
> maybe in the future the option to also call into driver callbacks to dump
> more driver state.

How about this:

drivers/gpu/drm/drm_gem.c:

#ifdef CONFIG_DEBUG_FS
void drm_gem_print(const struct drm_gem_object *obj, struct drm_printer *p)
{
     drm_printf(p, "name=%d refcount=%d start=%08lx size=%zu%s\n",
            obj->name, kref_read(&obj->refcount),
            drm_vma_node_start(&obj->vma_node), obj->size,
            obj->import_attach ? " (imported)" : "");
}
#endif


drivers/gpu/drm/drm_framebuffer.c:

#ifdef CONFIG_DEBUG_FS
static void drm_framebuffer_print(const struct drm_framebuffer *fb,
                   struct drm_printer *p)
{
     unsigned int i;

     drm_printf(p, "[FB:%d] %dx%d@%4.4s refcount=%d\n", fb->base.id,
            fb->width, fb->height, (char *)&fb->format->format,
            drm_framebuffer_read_refcount(fb));

     for (i = 0; i < fb->format->num_planes; i++) {
         drm_printf(p, "\t%u: offset=%d pitch=%d",
                i, fb->offsets[i], fb->pitches[i]);
         if (fb->obj[i]) {
             drm_printf(p, " GEM: ");
             drm_gem_print(fb->obj[i], p);
         } else {
             drm_printf(p, "\n");
         }
     }
}

static int drm_framebuffer_info(struct seq_file *m, void *data)
{
     struct drm_info_node *node = m->private;
     struct drm_device *dev = node->minor->dev;
     struct drm_printer p = drm_seq_file_printer(m);
     struct drm_framebuffer *fb;

     mutex_lock(&dev->mode_config.fb_lock);
     drm_for_each_fb(fb, dev)
         drm_framebuffer_print(fb, &p);
     mutex_unlock(&dev->mode_config.fb_lock);

     return 0;
}

static const struct drm_info_list drm_framebuffer_debugfs_list[] = {
     { "framebuffer", drm_framebuffer_info, 0 },
};

int drm_framebuffer_debugfs_init(struct drm_minor *minor)
{
     return drm_debugfs_create_files(drm_framebuffer_debugfs_list,
                 ARRAY_SIZE(drm_framebuffer_debugfs_list),
                 minor->debugfs_root, minor);
}
#endif


drivers/gpu/drm/drm_debugfs.c:

int drm_debugfs_init(struct drm_minor *minor, int minor_id,
              struct dentry *root)
{
...
     ret = drm_framebuffer_debugfs_init(minor);
     if (ret) {
         DRM_ERROR("Failed to create framebuffer debugfs files\n");
         return ret;
     }
...
}


Available names for the debugfs file:

$ grep -r "\"fbs\"" drivers/gpu/drm

$ grep -r "\"fb\"" drivers/gpu/drm
drivers/gpu/drm/tilcdc/tilcdc_drv.c:            { "fb", 
drm_fb_cma_debugfs_show, 0 },
drivers/gpu/drm/omapdrm/omap_debugfs.c: {"fb", fb_show, 0},
drivers/gpu/drm/tinydrm/mipi-dbi.c:     { "fb", drm_fb_cma_debugfs_show, 
0 },
drivers/gpu/drm/arm/hdlcd_drv.c:        { "fb", drm_fb_cma_debugfs_show, 
0 },
drivers/gpu/drm/msm/msm_debugfs.c:              { "fb", show_locked, 0, 
msm_fb_show },
drivers/gpu/drm/arc/arcpgu_drv.c:       { "fb", drm_fb_cma_debugfs_show, 
0 },

$ grep -r "\"framebuffer\"" drivers/gpu/drm

$ grep -r "\"framebuffers\"" drivers/gpu/drm
drivers/gpu/drm/tegra/drm.c:    { "framebuffers", 
tegra_debugfs_framebuffers, 0 },


Noralf.

> There's probably more stuff that we should list by default in debugfs,
> like blob properties and similar things.
> -Daniel
>
>> +
>> +/**
>> + * drm_gem_fb_debugfs_show() - Helper to list GEM backed framebuffer objects
>> + *                             in debugfs.
>> + * @m: Output file
>> + * @arg: Private data for the callback
>> + *
>> + * This function gives a debugfs representation of the framebuffers with their
>> + * backing GEM objects. See drm_debugfs_create_files() for more info.
>> + */
>> +int drm_gem_fb_debugfs_show(struct seq_file *m, void *arg)
>> +{
>> +	struct drm_info_node *node = m->private;
>> +	struct drm_device *dev = node->minor->dev;
>> +	struct drm_framebuffer *fb;
>> +
>> +	mutex_lock(&dev->mode_config.fb_lock);
>> +	drm_for_each_fb(fb, dev)
>> +		drm_gem_fb_describe(fb, m);
>> +	mutex_unlock(&dev->mode_config.fb_lock);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(drm_gem_fb_debugfs_show);
>> +#endif
>> +
>>   /**
>>    * drm_gem_fbdev_fb_create - Create a GEM backed &drm_framebuffer for fbdev
>>    *                           emulation
>> diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h
>> index 5ca7cdc3f527..1bb73d961aba 100644
>> --- a/include/drm/drm_gem_framebuffer_helper.h
>> +++ b/include/drm/drm_gem_framebuffer_helper.h
>> @@ -28,6 +28,12 @@ drm_gem_fb_create(struct drm_device *dev, struct drm_file *file,
>>   int drm_gem_fb_prepare_fb(struct drm_plane *plane,
>>   			  struct drm_plane_state *state);
>>   
>> +#ifdef CONFIG_DEBUG_FS
>> +struct seq_file;
>> +
>> +int drm_gem_fb_debugfs_show(struct seq_file *m, void *arg);
>> +#endif
>> +
>>   struct drm_framebuffer *
>>   drm_gem_fbdev_fb_create(struct drm_device *dev,
>>   			struct drm_fb_helper_surface_size *sizes,
>> -- 
>> 2.14.2
>>



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