>> For instance I had to introduce the device_setup module parameter in >> order to make my Audiophile USB pre-select 16bits OR 24bits mode >> because switching between the two modes while the device is turned >> on doesn't work: > > is it a linux kernel limitation or an harware issue (eg does switching > fork under windows)? Difficult to say... The Audiophile USB manual for Windows says that it is required to close any application when switching sample depth modes in the M-Audio Control Panel: but it is not necessary to turn off/on the device under windows. Under linux however, it is necessary to turn the device off, then initialize the module to only activate the Interfaces/AltSettings corresponding to the sample depth chosen and then turn on the device again ! I checked the USB messages sent and it seems that they are "equivalent" in windows/linux: I mean all Interfaces/AltSet are initialized to AltSet 0 then the Interfaces/AltSettings corresponding to the sample depth chosen are activated with a SELECT_INTERFACE message. However under windows when switching modes, there are 'sometimes' (I haven't investigated enough to analyze this)several AltSet resettings (Interfaces/AltSet initialized to AltSet 0) before setting again the correct Interfaces/AltSet. I tried several patches in order to avoid this limitation (reset the usb device, reset all interfaces to AltSet 0 several times before re-setting them...) but nothing proved to be usefull for this issue. Even if there is a hardware limitation, we should be able to avoid the Turn Off/On limitation by better looking at the windows driver... Thibault ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
