Hello, I'm developing a USB2.0/Full Speed (12MBit) audio device for Linux which needs high speed (>256Kbyes/sec)/low delay bidirectional data transfer. To ease development I'd prefer to skip driver development by implementing some device class, which already has a driver.
Currently I've made a preliminary firmware for implementing the CDC-ACM interface, however as Pavel kindly pointed out for me, currently only 64Kbyte/sec is achieveable with this driver. I've read the archives and from the discussions, I suspect that this is connected to the NO_FSBR flag.. Questions which popped out of my mind: 1. Is there some standard way to allow for >64Kbytes/sec using the 2.6.x CDC-ACM driver? (I mean without modification of the sources, but setting some #defines or such) I'd not mind a reasonably slower PCI bus.. 2. The audio device I'm developing will not output/request raw audio data (what is directly playable on speakers), so until now, I've not considered implementing the Audio class interface instead of CDC-ACM, but what do you think? Isochronous transfers would be okay for me (no problem in case of frame drops), but is it much harder to implement that compared to CDC? I've got only 3 endpoints.. 3. In case no standard class driver works out, which kernel driver do you recommend for study? I'd need a high speed/low delay IN and OUT channel and some way to give commands/retrieve status info from the device.. Would the NO_FSBR flag also pose a limitation in this case, or it only affects the CDC driver? I'd like to thank you for all information! Best regards, Istvan ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
