On Mon, Dec 10, 2012 at 11:53:27PM +0100, Timur wrote: > On 12/10/2012 11:08 PM, Greg KH wrote: > >On Mon, Dec 10, 2012 at 10:42:50PM +0100, Timur wrote: > >>Hi. I created a replacement kernel for the Nexus 7. Together with a > >>USB Y-cable, this mod enables charging the N7, while running the > >>device in USB host mode. People are using this to operate N7 + USB > >>DAC devices in their cars and other things. It's a fun project. > >> > >>I'm currently trying to solve an issue with slave devices not being > >>detectable after a sudden power loss. Slave devices will restart, > >>when external power comes back, but will be "not accepting address > >>xx, error -71". Would it make sense to try to back port some code > >>from a newer versions of ehci-hcd.c, including ehci_suspend() and > >>ehci_resume(), not existing in the 3.1.10 kernel of the N7? > >Why not just try a newer kernel and see if that works properly for you > >or not? There's nothing forcing the N7 to use the 3.1 kernel, is there? > > > >greg k-h > N7 is not using a vanilla kernel. Yes, I know that quite well :) > It is one thing to apply > modifications to the given code base. It would be far more difficult > (I think) to replace the kernel as a whole. Maybe I should back port > just as little code as possible? Or maybe I should try to back port > some full building blocks? Where to make the cut? I also wonder how > to make the system take advantage of ehci_suspend() and > ehci_resume(), both marked as "__maybe_unused". Who is calling these > methods? Look at the newer kernels for what is going on there. As for which is easier, that's up to you, there has been a lot of work to integrate the out-of-tree tegra and android code and get it merged to the main kernel since 3.1 was released over a year ago, so it depends on what you feel comfortable with doing. However, unless you are running the latest kernel.org release, there's usually not much we can help you out with here, as we don't know, or remember, what is going on in that very old release + odd-random-android patches. good luck, greg k-h -- 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
