From a85b4e7f4481c5a1ca89fa63c9c871151965075e Mon Sep 17 00:00:00 2001 From: "Brian J. Tarricone" Date: Sun, 21 Nov 2010 21:15:52 -0800 Subject: [PATCH] USB: ehci: disable LPM and PPCD for nVidia MCP89 chips Tested on MacBookAir3,1. Without this, we get EPROTO errors when fetching device config descriptors. Signed-off-by: Brian Tarricone Reported-by: Benoit Gschwind Tested-by: Edgar Hucek Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-pci.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c index 01bb72b71832..655f3c9f88bf 100644 --- a/drivers/usb/host/ehci-pci.c +++ b/drivers/usb/host/ehci-pci.c @@ -161,6 +161,18 @@ static int ehci_pci_setup(struct usb_hcd *hcd) if (pdev->revision < 0xa4) ehci->no_selective_suspend = 1; break; + + /* MCP89 chips on the MacBookAir3,1 give EPROTO when + * fetching device descriptors unless LPM is disabled. + * There are also intermittent problems enumerating + * devices with PPCD enabled. + */ + case 0x0d9d: + ehci_info(ehci, "disable lpm/ppcd for nvidia mcp89"); + ehci->has_lpm = 0; + ehci->has_ppcd = 0; + ehci->command &= ~CMD_PPCEE; + break; } break; case PCI_VENDOR_ID_VIA: -- 2.30.2