On Thu, Feb 26, 2009 at 08:52:09PM -0500, Paul O'Keefe wrote: > I was generous and gave the device 100,000 micro seconds to settle. And > boom (using your word!) all was well. It runs btool correctly, it syncs > correctly and it's happy. And that's a solution that should be generic > across the universe of devices we have to play with. I'll send Chris a > patch based on his latest version and we can move forward from there. I was finally able to reproduce the original timeout bug using a VM containing Debian Lenny. There were two issues confusing the debugging process. One was that the timeout appeared to be 1ms in gdb, but this was just a stack anomaly... stepping a bit farther changed gdb's results... probably due to using -O2 for the build. The other issue was a timeout in libusb's usb_bulk_read() function. This depended on: - a fairly modern tool chain (e.g. Debian Lenny or Ubuntu Jaunty) - a 2.6.28 kernel or higher (2.6.27 never shows this issue) My setup is a Debian Etch system running 2.6.28.7, and a Debian Lenny system running in a QEMU VM. btool (compiled with g++ 4.1.2 on Etch) runs fine on 2.6.28.7 and 2.6.28.4 on the bare Etch system. But if I run btool in the VM Lenny system using 2.6.28.4, compiled with g++ 4.3.2, I get a timeout. Adding a delay doesn't seem to help. All kernels I'm using for testing, on both systems, are compiled on the Etch system with gcc-3.3. I've been slowly running through a git bisect of the kernel to try to narrow this down. I have to be careful, since there was another USB bug that was fixed in 2.6.28.2 with commit: 73cb49b8860d9336ee4b24ecbc0d2358aff862f7 So far it's down to about 36 commits: good: eef70b217a7ab46e8e0cf75982ad75d8305d5591 bad: 0bc77ecbe4f69ff8ead1d2abfe84ca9ba2a7bca4 The bad commit fails twice. 1) compiled as-is, it gives error in usb_bulk_write(): -2 error submitting URB: No such file or directory 2) when the 2.6.28.2 patch is applied, it gives the timeout in usb_bulk_read() Sorry it's not narrowed down further... I ran out of time tonight. Thanks for any help you can provide. - Chris -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
