From 59d4ca50f3113ef5791645bf9577fb06794c9f52 Mon Sep 17 00:00:00 2001 From: Brian Tarricone Date: Thu, 18 Nov 2010 01:34:09 -0800 Subject: [PATCH] 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 --- drivers/usb/host/ehci-pci.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c index a1e8d27..aa79f98 100644 --- a/drivers/usb/host/ehci-pci.c +++ b/drivers/usb/host/ehci-pci.c @@ -148,6 +148,18 @@ 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: -- 1.7.2.2