On 07/22/2015 09:34 AM, Greg KH wrote: > On Wed, Jul 22, 2015 at 09:03:53AM -0500, Jeremy White wrote: >> On 07/09/2015 05:06 AM, Alex Elsayed wrote: >>> Alan Stern wrote: >>> >>>> On Mon, 6 Jul 2015, Jeremy White wrote: >>>> >>>>> Anything else fundamental to usbip that should inform the design of a >>>>> usbredir driver? usbip appears to be based off a 2004 vintage of >>>>> dummy_hcd. I'll look thoughtfully at the current dummy_hcd; please let >>>>> me know if there is anything else I should consider. >>>> >>>> One thing that springs to mind is USB-3 streams. When dummy-hcd was >>>> expanded to include USB-3, that was the major new ingredient. >>> >>> Another thing that comes to mind is that the USB-IF has its own official >>> standard for this kind of thing now, called Media-Agnostic USB[1]. In >>> November of 2014 a driver[2] was posted, followed by a second version[3], >>> and it is apparently being refined inside Intel[4]. >>> >>> [1] >>> http://www.usb.org/developers/docs/devclass_docs/Media_Agnostic_USB_v1.0.zip >>> [2] http://thread.gmane.org/gmane.linux.kernel/1820297 >>> [3] http://thread.gmane.org/gmane.linux.drivers.driver-project.devel/60498 >>> [4] http://article.gmane.org/gmane.linux.drivers.driver-project.devel/60757 >> >> Thanks for the pointer, Alex. >> >> I spent some time with the spec and their proposed code. It does seem >> plausible that XSpice could use a mausb/usbredir protocol converter. So if >> there was a mausb kernel module, I could potentially implement support in >> XSpice in user space and not need a usbredir module. >> >> I sent an email to the two developers at Intel to ask if there had been any >> further progress and if I could collaborate with them. I have not heard >> back. >> >> The MA spec is substantial and seems well thought out. But the usbredir >> protocol has the virtue of being relatively mature - it's 5 years old, with >> code in daily use. >> >> At this point it seems the best path forward is to continue work on the >> usbredir kernel module, which I will do unless I get some new information. > > Please work with the existing people, or with the existing spec, I don't > want to be adding multiple versions of this type of protocol to the > kernel. As it is, I really don't even want to take your code, given > that usbip is already there. Ignoring it isn't ok. The usbredir spec predates MA-USB by 4 years; it has greater claim to the title 'existing' than does MA-USB. I recognize that does not make it better, and I recognize the value of a spec from a standards body. But I also respect community standards in production use. And I did not and am not ignoring the MA-USB patch and spec. I privately wrote to the Intel authors of that patch a week ago; I've publicly included them in this thread as well. As far as I can tell, they've been silent on this front since November; I fear that they may have moved on, or that Intel is not actively working on this. None of the Intel authors listed on the MA-USB specification are kernel contributors, so I did not have a way to reach out to them. If you have the means to engage others, I would appreciate that. With no other input, my analysis was that it is better to proceed with the existing spec. It has a body of useful code, active users and developers, and I am certain it will solve my problem. Also, as for usbip, I'll point out that the existence of MA-USB corroborates Hans rationale for the need to supplant usbip. As I said, I will respond to any new information I receive. It would be great to have a kernel module developed (or at least approved) by seasoned hands at Intel. But how long should I wait? Cheers, Jeremy -- 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
