Messages in this thread Patch in this message | | | From | "Brian J. Tarricone" <> | Subject | [PATCH] ehci: disable LPM and PPCD for nVidia MCP89 chips | Date | Sat, 20 Nov 2010 16:32:55 -0800 |
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From: Brian Tarricone <brian@tarricone.org>
Tested on MacBookAir3,1. Without this, we get EPROTO errors when fetching device config descriptors.
Signed-off-by: Brian Tarricone <brian@tarricone.org> Reported-by: Benoit Gschwind <gschwind@gnu-log.net> Tested-by: Edgar Hucek <gimli@dark-green.com> Cc: Greg Kroah-Hartman <greg@kroah.com> --- 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
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