Re: [PATCH] Add support for SMSC UFX6000/7000 USB display adapters

[Greg KH <gregkh@suse.de>]

On Fri, Aug 12, 2011 at 12:06:55PM -0700, Bernie Thompson wrote:
> On Fri, Aug 12, 2011 at 8:56 AM, Greg KH <gregkh@suse.de> wrote:
> 
>     You can do the same for your calls to pr_debug() and other pr_* calls.
>     If you note in the header file for those functions, it suggests that
>     drivers should always call the dev_* versions instead of teh "raw" pr_*
>     functions, as you do have access to a struct device within your driver.
> 
> 
> A little background from udlfb: we weren't able to stick with dev_* calls 100%,
> because udlfb needed to survive USB device removal and the freeing of the
> USB-initiated device structure. This is because the framebuffer device needed
> to outlive it if a client was holding on to it.  In other words, it's born a
> two-headed beast (usb and fbdev), but the two faces of the device are killed
> off independently based on remaining ref counts.  So there are prints in there
> which will fault if converted to dev_* without this in mind.
> 
> Because of this, we had originally created our own dl_* wrapper around the pr_
> macros.
> 
> Then a later patch initiated by Paul (fbdev maintainer) changed those to
> uncustomized pr_ macros with a goal of uniformity with other drivers.  And that
> code is what SMSC started from.
> 
> So there's some complexity behind the choices here.  It might be good to keep
> common strategies between udlfb and smsc's driver, as the issues to consider
> are the same.

Ok, thanks for the background information, that makes sense.

But for stuff like the usb probe() call, that should always be dev_* as
you really do have a proper pointer.  So when you do have a valid struct
device, you should use it.

Although a lot of the pr_info() calls should be downgraded to pr_debug()
I imagine, to keep things from being so noisy.

thanks,

greg k-h