Re: [LAU] Intel Rate Matching Hub and USB soundcards

Jeremy Jongepier wrote: The "Rate Matching" behaves just like a normal USB hub; this design choice does not introduce any problems by itself. However, the USB controllers in these chipsets (5 and 3400 series) are just plain buggy; the bug list ("specification update") says: | 6. Intel® 5 Series Chipset and Intel® 3400 Series Chipset Full-Speed | USB Isochronous Packet Truncation | | Problem: Full-Speed isochronous-out transactions with multi-frame | packets may be truncated, in the presence of Full or Low-Speed USB | asynchronous transactions. | • For this to occur, two devices, one performing Full-Speed | isochronous-out transactions and one performing asynchronous | transactions must be connected to the same USB controller | (Ports 0-7 and 8-13). | | Implication: In the case of a USB audio device this issue may result | in no audible impact or audible artifacts such as pops and clicks. | | Note: | • High-Speed and Low-Speed USB devices are not impacted by this issue. | • Only devices supporting Full-Speed isochronous-out transactions that | Intel is aware of are audio devices, such as sound adapters, | speakers, and headphones. | • Intel has only observed the issue when a Full-Speed audio devices | and Full-Speed USB web camera are connected to the same USB | controller. | | Workaround: None. | Status: Fixed (that is, fixed in chip revision B3) Regards, Clemens