Re: [PATCH v4 3/3] usb: dwc3: Log dwc3 address in traces

From: Thinh Nguyen

Date: Wed Jan 14 2026 - 17:55:04 EST


On Wed, Jan 14, 2026, Greg Kroah-Hartman wrote:
> On Wed, Jan 14, 2026 at 03:37:48PM +0530, Prashanth K wrote:
> > + * @address: Cached lower 32-bit base address to be used for logging.
>
> Why are 32bits enough / ok? Why not use the full 64 that you really
> have? What happens if you have 2 devices with just the upper 32 bits
> different?
>
> This is a resource value, so why not use the proper type for it?
>

This is only intented to be used for logging, so I suggested to use u32.
I want to avoid treating this struct member as a phys_addr_t where it
may be misused.

As for the reason to capture only the lower 32-bit, it's just base on
what I've seen so far. That I have not seen designs where the 2 or more
instances are placed that far apart and share the same lower 32-bit.
It's a bit nicer to shorten the address print at the start of a
tracepoint. But if it's insufficient, there's no problem with using
64-bit.

BR,
Thinh