Re: [PATCH 2/2] usb: core: Add tracepoints for device allocation and state changes

[Alan Stern <stern@rowland.harvard.edu>]

On Tue, Oct 14, 2025 at 08:05:25AM +0800, Kuen-Han Tsai wrote:
> Hi Alan,
> 
> On Mon, Oct 13, 2025 at 9:20 PM Alan Stern <stern@rowland.harvard.edu> wrote:
> >
> > Suggestion: Rather than printing the meaningless numerical value of
> > __entry->state, print the string value returned by
> > usb_state_string(__entry->state).
> 
> I kept it consistent with the udc_log_gadget tracepoint, which also
> uses the numerical value for the USB state.
> 
> If we change the state to a string, should we convert the speed field
> to a string using usb_speed_string()?
> 
> I lean toward keeping both as numerical values, but I am happy to
> switch both to strings if you prefer. Please let me know what you
> think is best.

I agree that if one of them uses strings then so should the other.

As for whether you should change them...  I don't care very much, since 
I haven't used tracepoints in my gadget debugging.  I was just thinking 
of what other people might like.

Greg, do you have a recommendation?

Alan Stern