Re: Module aliases etc.

[Mark Morgan Lloyd <markMLl.debian-arm@telemetry.co.uk>]

On 20/02/18 16:45, Lennart Sorensen wrote:
> On Sat, Feb 17, 2018 at 12:05:13PM +0000, Mark Morgan Lloyd wrote:
> > I'm trying to disentangle some driver issues so that I can backport a module
> > for a colleague with a weird peripheral. Can anybody tell me what the "b"
> > field here is, and in particular the significance of the number (3 or 5 in
> > the example below)?
> >
> > alias:          hid:b0003g*v0000056Ep0000010D
> > alias:          hid:b0003g*v0000056Ep0000010C
> > alias:          hid:b0003g*v0000056Ep000000FF
> > alias:          hid:b0003g*v0000056Ep000000FE
> > alias:          hid:b0005g*v0000056Ep00000061
> >
> > I'd assumed from udev/hwdb that it was a bus identifier applicable to
> > something that was actually plugged in, but I'm curious to see it varying on
> > a virgin system that's never seen the peripheral in question.
>
> Well the kernel source code says:
>
>          return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
>                           hdev->bus, hdev->group, hdev->vendor, hdev->product);
>
> Also:
>
>         switch (hdev->bus) {
>          case BUS_USB:
>                  bus = "USB";
>                  break;
>          case BUS_BLUETOOTH:
>                  bus = "BLUETOOTH";
>                  break;
>          case BUS_I2C:
>                  bus = "I2C";
>                  break;
>          default:
>                  bus = "<UNKNOWN>";
>          }
>
> So it appears to be a bus type.  3 is USB, 5 is BLUETOOTH according to input.h

Thanks very much, got it. So apparently includes things like the 8042 
keyboard controller and so on.

--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]