ehci: workaround for pci quirk timeout on ExoPC

The BIOS handoff for the unused EHCI controller on the ExoPC tablet
hangs for 90 seconds on boot.  Detect that device, skip negotiation
and force the handoff.
Signed-off-by: NAndy Ross <andy.ross@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/pci-quirks.c

@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include "pci-quirks.h"
 #include "xhci-ext-caps.h"
 
@@ -507,9 +508,20 @@ static void __devinit ehci_bios_handoff(struct pci_dev *pdev,
 					void __iomem *op_reg_base,
 					u32 cap, u8 offset)
 {
-	int msec, tried_handoff = 0;
+	int try_handoff = 1, tried_handoff = 0;
+
+	/* The Pegatron Lucid (ExoPC) tablet sporadically waits for 90
+	 * seconds trying the handoff on its unused controller.  Skip
+	 * it. */
+	if (pdev->vendor == 0x8086 && pdev->device == 0x283a) {
+		const char *dmi_bn = dmi_get_system_info(DMI_BOARD_NAME);
+		const char *dmi_bv = dmi_get_system_info(DMI_BIOS_VERSION);
+		if (dmi_bn && !strcmp(dmi_bn, "EXOPG06411") &&
+		    dmi_bv && !strcmp(dmi_bv, "Lucid-CE-133"))
+			try_handoff = 0;
+	}
 
-	if (cap & EHCI_USBLEGSUP_BIOS) {
+	if (try_handoff && (cap & EHCI_USBLEGSUP_BIOS)) {
 		dev_dbg(&pdev->dev, "EHCI: BIOS handoff\n");
 
 #if 0
@@ -534,20 +546,23 @@ static void __devinit ehci_bios_handoff(struct pci_dev *pdev,
 	}
 
 	/* if boot firmware now owns EHCI, spin till it hands it over. */
-	msec = 1000;
-	while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
-		tried_handoff = 1;
-		msleep(10);
-		msec -= 10;
-		pci_read_config_dword(pdev, offset, &cap);
+	if (try_handoff) {
+		int msec = 1000;
+		while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
+			tried_handoff = 1;
+			msleep(10);
+			msec -= 10;
+			pci_read_config_dword(pdev, offset, &cap);
+		}
 	}
 
 	if (cap & EHCI_USBLEGSUP_BIOS) {
 		/* well, possibly buggy BIOS... try to shut it down,
 		 * and hope nothing goes too wrong
 		 */
-		dev_warn(&pdev->dev, "EHCI: BIOS handoff failed"
-			 " (BIOS bug?) %08x\n", cap);
+		if (try_handoff)
+			dev_warn(&pdev->dev, "EHCI: BIOS handoff failed"
+				 " (BIOS bug?) %08x\n", cap);
 		pci_write_config_byte(pdev, offset + 2, 0);
 	}