r8152: Increase USB control msg timeout to 5000ms as per spec

According to the comment next to USB_CTRL_GET_TIMEOUT and
USB_CTRL_SET_TIMEOUT, although sending/receiving control messages is
usually quite fast, the spec allows them to take up to 5 seconds.
Let's increase the timeout in the Realtek driver from 500ms to 5000ms
(using the #defines) to account for this.

This is not just a theoretical change. The need for the longer timeout
was seen in testing. Specifically, if you drop a sc7180-trogdor based
Chromebook into the kdb debugger and then "go" again after sitting in
the debugger for a while, the next USB control message takes a long
time. Out of ~40 tests the slowest USB control message was 4.5
seconds.

While dropping into kdb is not exactly an end-user scenario, the above
is similar to what could happen due to an temporary interrupt storm,
what could happen if there was a host controller (HW or SW) issue, or
what could happen if the Realtek device got into a confused state and
needed time to recover.

This change is fairly critical since the r8152 driver in Linux doesn't
expect register reads/writes (which are backed by USB control
messages) to fail.

Fixes: ac718b69301c ("net/usb: new driver for RTL8152")
Suggested-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 0c13d99..482957b 100644 (file)
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -1212,7 +1212,7 @@ int get_registers(struct r8152 *tp, u16 value, u16 index, u16 size, void *data)
 
        ret = usb_control_msg(tp->udev, tp->pipe_ctrl_in,
                              RTL8152_REQ_GET_REGS, RTL8152_REQT_READ,
-                             value, index, tmp, size, 500);
+                             value, index, tmp, size, USB_CTRL_GET_TIMEOUT);
        if (ret < 0)
                memset(data, 0xff, size);
        else
@@ -1235,7 +1235,7 @@ int set_registers(struct r8152 *tp, u16 value, u16 index, u16 size, void *data)
 
        ret = usb_control_msg(tp->udev, tp->pipe_ctrl_out,
                              RTL8152_REQ_SET_REGS, RTL8152_REQT_WRITE,
-                             value, index, tmp, size, 500);
+                             value, index, tmp, size, USB_CTRL_SET_TIMEOUT);
 
        kfree(tmp);
 
@@ -9494,7 +9494,8 @@ static u8 __rtl_get_hw_ver(struct usb_device *udev)
 
        ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                              RTL8152_REQ_GET_REGS, RTL8152_REQT_READ,
-                             PLA_TCR0, MCU_TYPE_PLA, tmp, sizeof(*tmp), 500);
+                             PLA_TCR0, MCU_TYPE_PLA, tmp, sizeof(*tmp),
+                             USB_CTRL_GET_TIMEOUT);
        if (ret > 0)
                ocp_data = (__le32_to_cpu(*tmp) >> 16) & VERSION_MASK;