Re: [PATCH v2] usb: usbtmc: reject invalid interrupt endpoints

Michal Pecio
2026-04-30T21:04:29Z

On Thu, 30 Apr 2026 22:48:49 +0200, Michal Pecio wrote:
> The only change to support USB488 devices with wMaxPacketSize == 1
> should be increasing URB size to at least 2 bytes. But I wouldn't
> bother when no such HW is known to exist, and surely not as part of
> a barely related bugfix patch.

Correction: I noticed that USB488 spec Table 22 requires wMaxPacketSize
to be exactly 0x02, unless the device sends vendor notifications.

One could argue that 0x01 is covered by this exception, but that's
obviously against the intent.

So for bInterfaceProtocol 1 devices, requiring wMaxPacketSize >= 2
should be OK, but bInterfaceProtocol 0 devices are unclear.

Regards,
Michal