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Commit 40633219 authored by Mika Kuoppala's avatar Mika Kuoppala Committed by Daniel Vetter
Browse files

drm/i915: Add debugfs entry to read/write next_seqno 



This is needed for testing seqno wrapping. Be careful to not bump next_seqno
more than 0x7FFFFFFF at a time (between some handled requests) as
i915_seqno_passed() can't handle bigger difference in between.

v2: Address review comments from Chris Wilson.

Signed-off-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Acked-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
[danvet: Squash in fixup to properly remove the debugfs file on driver
unload again.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 1a240d4d

drivers/gpu/drm/i915/i915_debugfs.c

+88 −0
Original line number Diff line number Diff line
@@ -843,6 +843,86 @@ static const struct file_operations i915_error_state_fops = { 
	.release = i915_error_state_release,

};



static ssize_t

i915_next_seqno_read(struct file *filp,

		 char __user *ubuf,

		 size_t max,

		 loff_t *ppos)

{

	struct drm_device *dev = filp->private_data;

	drm_i915_private_t *dev_priv = dev->dev_private;

	char buf[80];

	int len;

	int ret;



	ret = mutex_lock_interruptible(&dev->struct_mutex);

	if (ret)

		return ret;



	len = snprintf(buf, sizeof(buf),

		       "next_seqno :  0x%x\n",

		       dev_priv->next_seqno);



	mutex_unlock(&dev->struct_mutex);



	if (len > sizeof(buf))

		len = sizeof(buf);



	return simple_read_from_buffer(ubuf, max, ppos, buf, len);

}



static ssize_t

i915_next_seqno_write(struct file *filp,

		      const char __user *ubuf,

		      size_t cnt,

		      loff_t *ppos)

{

	struct drm_device *dev = filp->private_data;

	drm_i915_private_t *dev_priv = dev->dev_private;

	char buf[20];

	u32 val = 1;

	int ret;



	if (cnt > 0) {

		if (cnt > sizeof(buf) - 1)

			return -EINVAL;



		if (copy_from_user(buf, ubuf, cnt))

			return -EFAULT;

		buf[cnt] = 0;



		ret = kstrtouint(buf, 0, &val);

		if (ret < 0)

			return ret;

	}



	if (val == 0)

		return -EINVAL;



	ret = mutex_lock_interruptible(&dev->struct_mutex);

	if (ret)

		return ret;



	if (i915_seqno_passed(val, dev_priv->next_seqno)) {

		dev_priv->next_seqno = val;

		DRM_DEBUG_DRIVER("Advancing seqno to %u\n", val);

	} else {

		ret = -EINVAL;

	}



	mutex_unlock(&dev->struct_mutex);



	return ret ?: cnt;

}



static const struct file_operations i915_next_seqno_fops = {

	.owner = THIS_MODULE,

	.open = simple_open,

	.read = i915_next_seqno_read,

	.write = i915_next_seqno_write,

	.llseek = default_llseek,

};



static int i915_rstdby_delays(struct seq_file *m, void *unused)

{

	struct drm_info_node *node = (struct drm_info_node *) m->private;
@@ -2107,6 +2187,12 @@ int i915_debugfs_init(struct drm_minor *minor) 
	if (ret)

		return ret;



	ret = i915_debugfs_create(minor->debugfs_root, minor,

				 "i915_next_seqno",

				 &i915_next_seqno_fops);

	if (ret)

		return ret;



	return drm_debugfs_create_files(i915_debugfs_list,

					I915_DEBUGFS_ENTRIES,

					minor->debugfs_root, minor);
@@ -2130,6 +2216,8 @@ void i915_debugfs_cleanup(struct drm_minor *minor) 
				 1, minor);

	drm_debugfs_remove_files((struct drm_info_list *) &i915_error_state_fops,

				 1, minor);

	drm_debugfs_remove_files((struct drm_info_list *) &i915_next_seqno_fops,

				 1, minor);

}



#endif /* CONFIG_DEBUG_FS */