[PATCH 4.9 025/105] xhci: Fix sleeping with spin_lock_irq() held in ASmedia 1042A workaround

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>

commit 4ec1cd3eeeee7ccc35681270da028dbc29ca7bbd upstream.

The flow control workaround for ASM1042A xHC hosts sleeps between
register polling. The workaround gets called in several places, among
them with spin_lock_irq() held when xHC host is resumed or hoplug removed.

This was noticed as kernel panics at resume on a Dell XPS15 9550 with
TB16 thunderbolt dock.

Avoid sleeping with spin_lock_irq() held, use udelay() instead

The original workaround was added to 4.9 and 4.12 stable releases,
this patch needs to be applied to those as well.

Fixes: 9da5a1092b13 ("xhci: Bad Ethernet performance plugged in ASM1042A host")
Reported-by: Jose Marino <marinoj@xxxxxxx>
Tested-by: Jose Marino <marinoj@xxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/host/pci-quirks.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -447,7 +447,7 @@ static int usb_asmedia_wait_write(struct
 		if ((value & ASMT_CONTROL_WRITE_BIT) == 0)
 			return 0;
 
-		usleep_range(40, 60);
+		udelay(50);
 	}
 
 	dev_warn(&pdev->dev, "%s: check_write_ready timeout", __func__);