From 3df7169e73fc1d71a39cffeacc969f6840cdf52b Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 10 Sep 2010 16:37:05 -0400 Subject: OHCI: work around for nVidia shutdown problem MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Reported-by: Pali Rohár Signed-off-by: Alan Stern CC: David Brownell Tested-by: Pali Rohár CC: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ohci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/usb/host/ohci.h') diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h index 5bf15fed0d9..51facb985c8 100644 --- a/drivers/usb/host/ohci.h +++ b/drivers/usb/host/ohci.h @@ -403,6 +403,7 @@ struct ohci_hcd { #define OHCI_QUIRK_HUB_POWER 0x100 /* distrust firmware power/oc setup */ #define OHCI_QUIRK_AMD_ISO 0x200 /* ISO transfers*/ #define OHCI_QUIRK_AMD_PREFETCH 0x400 /* pre-fetch for ISO transfer */ +#define OHCI_QUIRK_SHUTDOWN 0x800 /* nVidia power bug */ // there are also chip quirks/bugs in init logic struct work_struct nec_work; /* Worker for NEC quirk */ -- cgit v1.2.3-70-g09d2