On Sat, Jul 31, 2010 at 12:56:50PM -0700, Greg KH wrote: > On Fri, Jul 30, 2010 at 07:19:41PM -0700, David VomLehn wrote: > > Make reservation of write URB atomic. > > Why? What is this fixing? What is the problem you are seeing? More description: This is intended to fix a problem seen with the Amtel sam-ba tool by Alexander Stein (alexander.stein@xxxxxxxxxxxxxxxxxxxxx). It appears when using an A91 controller. He bisected it to commit: 8e8dce065088833fc418bfa5fbf035cb0726c04c: USB: use kfifo to buffer usb-generic serial writes The current patch fixes a problem when using a USB serial device as the kernel console and as /dev/console. The URB allocation is not atomic and an URB can be doubly allocated, leading to a continual rejection of URB submissions. The fix puts all pieces of the URB allocation in the same spinlock-protected section of code. Having said that... This fix was developed because, after Alexander's email, I took a look at my USB console and found that it, too, was experiencing a hang. I assumed that this hang was the same as the one Alexander is seeing and developed this fix. It's a good fix for *a* hang, but after thinking about this a bit, I'm not sure this is a fix for *Alexander's* hang. Alexander, please apply this patch and let me know whether this fixes your problem. If not, I'll need to work with you to get more information since I don't have the sam-ba tool or an A91 controller. > thanks, > > greg k-h -- David VL -- 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
