On Mon, 18 May 2009, julien de ROSNY wrote: > When I plug a dvb-t usb stick and a memory usb stick and I copy a large file from the memory stick to the hard drive, the dvb-t reception is bad. > The same behaviour occurs when I plug a wifi usb stick and the dvb-t stick. > > The lsusb command gives : > > Bus 001 Device 007: ID 148f:2573 Ralink Technology, Corp. RT2501USB Wireless Adapter > Bus 001 Device 002: ID 0413:6026 Leadtek Research, Inc. WinFast DTV Dongle (warm state) > ings > > Is it normal that the two isb2 devices shares the same bus? Yes. > Is a bus equivalent to a usb hub.? No, it's more like a USB host controller. You can have many hubs all on the same bus, if they are attached to the same controller. > If yes, the problem looks like a same hub share the two usb2 devices. So due to the limited bandwidth, dvb-t data are lost during the coping of the data from the memeory stick. No. Realtime devices like your dvb-t stick are guaranteed a certain amount of bandwith on the USB bus, and bulk-data devices like your memory stick get whatever bandwidth is left over. > I must say that the dvb-t and memory (or wifi) sticks are plugged on two different usb connectors directly on the motherboard. > Is there a way to force different bus assignation to a usb device? Sure. Plug the device into a different port. The ports aren't all on the same bus. Alan Stern -- 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
