Hi there, On Sun, 28 Dec 2003, Kevin Boergens wrote:
> Everywhere I read that the ehci-hcd module only works in combination > with one of the USB 1.1 controllers. But I have connencted one USB-CD > via usbcore + ehci-hcd + usb-storage. No other usb-module loaded and > everything works fine. How is this to be explained? I don't think that's quite what it says in the documentation. If you have a USB1.x device plugged into a USB2-capable hub then the 1.x device will want to use a USB1.x hub for the communication and that's why there's a need for the USB1.x hub as well as the USB2 hub on the same physical connector. But as I understand it if you have only a USB2 device connected to the hub, the USB1.x hub won't be used, so I guess the driver won't be needed either. However, never having made a USB2 device work successfully under Linux, this is all theory to me. > OT: One big advantage of SCSI against ATA always was that an SCSI > controller works (e.g. copying a file from one disk to another) without > much CPU load (I don't know whether this is right, but I heard it). Er, in general I don't think you can make that generalization. Both types of device can use DMA transfers, which is what I think you mean. Real SCSI (as opposed to the SCSI emulation layers which are seen quite a lot in the USB world) is capable of better performance but it's not just a question of CPU load - the physical connections and electrical specifications are completely different. > Does the same advantage also exist with USB-controllers. Or is CPU > load a problem? USB can be rather heavy on the CPU but it depends waht you're doing with it. A USB mouse for instance isn't capable of generating enough activity to make a 386 break into a sweat. For looking at the loads on your machine read about the 'top' utility for example. 73, Ged. ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
