On Thu, Sep 24, 2015 at 02:09:41PM +0200, Krzysztof Opasiak wrote: > Let's start from the beginning. Your device use ISO endpoints which means > that host allocates specific amount of bandwidth on the bus. More over, > interfaces in your devices has many alternate settings. Probably each of > them reserves different amount of bandwidth. When you connect your first > device, driver selects the highest possible quality and allocate maximum > bandwidth. When you connect second device driver tries to select altsetting > for which there is enough bandwidth left but as you see this fail. So we > get: I'm sorry, I should have mentioned an important detail here. There is no kernel driver for my card; I drive it from userspace with libusb-1.0. So I'm the one setting the alternates. The cards start out in alternate 0, so the scenario you're outlining shouldn't exist; and indeed, the setting the first card to 4 (the low-bandwidth alternate) works just fine, it's setting the second one that's the problem. /* Steinar */ -- Homepage: http://www.sesse.net/ -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
