On Thu, 17 Mar 2005, Steve Fosdick wrote: > On 16/03/05 21:57:18, you wrote: > > > This means that the PCI bus on your laptop was overloaded, and the USB > > controller couldn't keep up with the demand for data. Overall it sure > > looks like everything comes down to insufficient bandwidth. > > Just doing a quick clalculation, audio at 44100, 24 bit stereo would > require 2.7 Mbit/sec bandwidth for the raw audio, plus whatever overhead > is added for USB (assuming 24 bit samples get transferred in 32 bit > words). A 32 bit 33Mhz PCI bus should have a bandwidth of approx. > 1Gbit/sec (125 Mbytes/sec) minus overhead. > > So, I am not sure what can be using the extra bandwidth as the problem > appears even when the PC is almost completely idle, i.e. CPU usage > negligable, nothing drawing to the screen and no noticable I/O to disk, > CD or network etc. Interestingly it does get worse with disk I/O.
It could be there's a problem with the audio driver, causing it to use more bandwidth than it should. > Does Linux schedule activity on the PCI bus or do all drivers try to > operate their own hardware as fast as possible? PCI activity is not scheduled. Alan Stern ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
