On Tue, Jun 04, 2019 at 11:39:21AM -0700, Guenter Roeck wrote: > On Tue, Jun 4, 2019 at 11:35 AM Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Tue, Jun 04, 2019 at 01:58:38PM -0300, Ezequiel Garcia wrote: > > > Hey Greg, > > > > > > > > + dev_info(&pdev->dev, "Created misc device /dev/%s\n", > > > > > + data->misc.name); > > > > > > > > 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. > > > > For you, yes. For someone with 30000 devices attached to their system, > > it is not, and causes booting to take longer than it should be. > > > > > 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; > > > error: > > > media_entity_cleanup(&sd->entity); > > > > > > In some subsystems, it's even a behavior I'm more or less relying on: > > > > > > $ git grep v4l2_info.*registered drivers/media/ | wc -l > > > 26 > > > > > > 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. > > > > Its better to be quiet, which is why the "default driver registration" > > macros do not have any printk messages in them. When converting drivers > > over to it, we made the boot process much more sane, don't try to go and > > add messages for no good reason back in please. > > > > dynamic debugging can be enabled on a module and line-by-line basis, > > even from the boot command line. So if you need debugging, you can > > always ask someone to just reboot or unload/load the module and get the > > message that way. > > > > Can we by any chance make this an official policy ? I am kind of tired > having to argue about this over and over again. Sure, but how does anyone make any "official policy" in the kernel? :) I could just go through and delete all "look ma, a new driver/device!" messages, but that might be annoying... thanks, greg k-h
