On Fri, 20 Oct 2006, Laurent Pinchart wrote: > > Did anything ever come out of all this? Was the problem located and was > > the firmware fixed? > > As far as I know, no :-( > > Martin has finished his thesis and doesn't work at Logitech anymore. He told > me before leaving that the firmware developers will definitely implement a > workaround for the hardware bug.
Did they ever determine exactly what the bug was and how to trigger it? One aspect was quite clear in the logs Martin made available: The device responded to PING with ACK when it should have used NAK. But that alone wasn't the cause of the problem. > New cameras won't suffer from the problem, but we have a bunch of old cameras > in the field that work fine under Windows and fail miserably under Linux. I'd > really like to solve the problem on the software side. There is very little > the driver can do, as the issue lies at the USB level. Are you sure it's not at the driver level? Maybe something to do with the time delay surrounding control transfers? > The device is at fault, but Windows doesn't trigger the bug. I'm pretty sure > Windows and Linux handle control transfers differently. Can you see another > explanation ? I'm not familiar with the USB stack internals, but I wouldn't > mind getting my hands dirty. Could you tell me where I should look at ? > Anything that comes to your mind ? I don't know of any particular differences between the ways Windows and Linux carry out control transfers. It's specified pretty rigidly by the USB spec and the details are handled by the hardware in the host controller. I don't think looking at the low-level driver will help much; not at first, anyway. You have to start by knowing exactly what triggers the bug, maybe verifying this with a detailed comparison of the Windows and Linux USB bus traces. Martin's questions and statements about the traces showed that he didn't fully understand the issues involved. Once we are certain of the cause of the problem, then we can think about how to avoid it. Alan Stern ------------------------------------------------------------------------- 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 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
