Re: [9front] bug: nusb fails to set report protocol with a stall error

[Romano <unobe@cpan.org>]

I had noticed this consistently on my rpi4, but hadn't had time to look at it. It generally occurs when I plug in my Logitech MX Ergo mouse.

On November 20, 2020 12:58:24 PM UTC, Nick Owens <mischief@offblast.org> wrote:
>on my desktop with usb3, i see 'setproto: Stall Error' with certain
>devices.
>
>when using nusb/kb with my tex shinobi, i see a stall error, but only
>for the builtin trackpoint.
>
>when using nusb/joy i see a stall error with my ps4 controller.
>
>with a short test, i just removed the command to set the interface
>protocol, and now both devices work.
>
>after looking at the HID 1.11 spec, it seems like if a HID interface
>descriptor has an interface subclass of 0, support for set protocol is
>optional.
>
>here is a patch which avoids setproto for devices which might not
>support it, and it works for both my tex shinobi and ps4 controller.
>
>thoughts?
>
>diff --git a/sys/src/cmd/nusb/joy/joy.c b/sys/src/cmd/nusb/joy/joy.c
>--- a/sys/src/cmd/nusb/joy/joy.c
>+++ b/sys/src/cmd/nusb/joy/joy.c
>@@ -222,6 +222,12 @@ setproto(KDev *f, int eid)
> 		proto = Reportproto;
> 	}else
> 		kbfatal(f, "no report");
>+
>+	// if a HID's subclass code is 0, it may not support setproto,
>+	// and is always initialized in report mode.
>+	if(((iface->csp>>8)&0xFF) == 0)
>+		return 0;
>+
>	return usbcmd(f->dev, Rh2d|Rclass|Riface, Setproto, proto, id, nil,
>0);
> }
> 
>diff --git a/sys/src/cmd/nusb/kb/kb.c b/sys/src/cmd/nusb/kb/kb.c
>--- a/sys/src/cmd/nusb/kb/kb.c
>+++ b/sys/src/cmd/nusb/kb/kb.c
>@@ -368,6 +368,12 @@ setproto(Hiddev *f, int eid)
> 		}
> 		proto = Bootproto;
> 	}
>+
>+	// if a HID's subclass code is 0, it may not support setproto,
>+	// and is always initialized in report mode.
>+	if(((iface->csp>>8)&0xFF) == 0)
>+		return 0;
>+
>	return usbcmd(f->dev, Rh2d|Rclass|Riface, Setproto, proto, iface->id,
>nil, 0);
> }
>