Re: [PATCH 03/10] mfd / platform: cros_ec: Miscellaneous character device to talk with the EC

From: Ezequiel Garcia
Date: Tue Jun 04 2019 - 13:02:55 EST

Hey Greg,

> > + dev_info(&pdev->dev, "Created misc device /dev/%s\n",
> > + data->;
> No need to be noisy, if all goes well, your code should be quiet.

I sometimes wonder about this being noise or not, so I will slightly
hijack this thread for this discussion.

>From a kernel developer point-of-view, or even from a platform
developer or user with a debugging hat point-of-view, having
a "device created" or "device registered" message is often very useful.

In fact, I wish people would do this more often, so I don't have to
deal with dynamic debug, or hack my way:

diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
index 4589631798c9..473549b26bb2 100644
--- a/drivers/media/i2c/ov5647.c
+++ b/drivers/media/i2c/ov5647.c
@@ -603,7 +603,7 @@ static int ov5647_probe(struct i2c_client *client,
if (ret < 0)
goto error;

- dev_dbg(dev, "OmniVision OV5647 camera driver probed\n");
+ dev_info(dev, "OmniVision OV5647 camera driver probed\n");
return 0;

In some subsystems, it's even a behavior I'm more or less relying on:

$ git grep v4l2_info.*registered drivers/media/ | wc -l

And on the downsides, I can't find much. It's just one little line,
that is not even noticed unless you have logging turned on.