From: Brian J. Tarricone <brian@tarricone.org>
Date: Mon, 22 Nov 2010 05:15:52 +0000 (-0800)
Subject: USB: ehci: disable LPM and PPCD for nVidia MCP89 chips
X-Git-Tag: firefly_0821_release~9833^2~79^2^2~82
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f9a65bd413df09aaee5b013a2e51fd4aece687fa;p=firefly-linux-kernel-4.4.55.git

USB: ehci: disable LPM and PPCD for nVidia MCP89 chips

commit a85b4e7f4481c5a1ca89fa63c9c871151965075e upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index a1e8d273103f..8d24d1c5e6a2 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: