[PATCH] ehci: disable LPM and PPCD for nVidia MCP89 chips
From: Brian J. Tarricone
Date: Sat Nov 20 2010 - 19:33:23 EST
From: Brian Tarricone <brian@xxxxxxxxxxxxx>
Tested on MacBookAir3,1. Without this, we get EPROTO errors when
fetching device config descriptors.
Signed-off-by: Brian Tarricone <brian@xxxxxxxxxxxxx>
Reported-by: Benoit Gschwind <gschwind@xxxxxxxxxxx>
Tested-by: Edgar Hucek <gimli@xxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <greg@xxxxxxxxx>
---
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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