On Thu, 23 Jun 2011, Paul Gortmaker wrote: > From: Alan Stern <[email protected]> > > ------------------- > This is a commit scheduled for the next v2.6.34 longterm release. > If you see a problem with using this for longterm, please comment. > ------------------- > > commit 3df7169e73fc1d71a39cffeacc969f6840cdf52b upstream. > > This patch (as1417) fixes a problem affecting some (or all) nVidia > chipsets. When the computer is shut down, the OHCI controllers > continue to power the USB buses and evidently they drive a Reset > signal out all their ports. This prevents attached devices from going > to low power. Mouse LEDs stay on, for example, which is disconcerting > for users and a drain on laptop batteries. > > The fix involves leaving each OHCI controller in the OPERATIONAL state > during system shutdown rather than putting it in the RESET state. > Although this nominally means the controller is running, in fact it's > not doing very much since all the schedules are all disabled. However > there is ongoing DMA to the Host Controller Communications Area, so > the patch also disables the bus-master capability of all PCI USB > controllers after the shutdown routine runs. > > The fix is applied only to nVidia-based PCI OHCI controllers, so it > shouldn't cause problems on systems using other hardware. As an added > safety measure, in case the kernel encounters one of these running > controllers during boot, the patch changes quirk_usb_handoff_ohci() > (which runs early on during PCI discovery) to reset the controller > before anything bad can happen.
This commit caused problems on systems using later NVIDIA hardware. It shouldn't be merged unless the upstream commit 2b7aaf503d56216b847c8265421d2a7d9b42df3e is merged also. Alan Stern _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
