dwc2 USB controller hangs with lan78xx

This bug is the combination of dwc2 USB controller and lan78xx
USB ethernet controller, which is the combination in use on
the Raspberry Pi Model 3 B+.

When the host attempts to receive a packet, but a packet has not
arrived, the lan78xx controller responds by setting BIR
(Bulk-In Empty Response) to NAK. Unfortunately, this hangs
the USB controller and requires the USB controller to
be reset.

The fix proposed is to have the lan78xx controller respond
by setting BIR to ZLP.

Signed-off-by: Andrew Thomas <andrew.thomas@oracle.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Alexander Graf <agraf@suse.de>

diff --git a/drivers/usb/eth/lan78xx.c b/drivers/usb/eth/lan78xx.c
index c5ff3797cfb20824fd0b9ab3bab472a4c21ab47b..e8ee6650bc4ad31bb89d143e1c8d7add6677c126 100644 (file)
--- a/drivers/usb/eth/lan78xx.c
+++ b/drivers/usb/eth/lan78xx.c
@@ -296,7 +296,7 @@ static int lan78xx_basic_reset(struct usb_device *udev,
        ret = lan7x_read_reg(udev, LAN78XX_USB_CFG0, &val);
        if (ret)
                return ret;
-       val |= LAN78XX_USB_CFG0_BIR;
+       val &= ~LAN78XX_USB_CFG0_BIR;
        return lan7x_write_reg(udev, LAN78XX_USB_CFG0, val);
 }