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@xxxxxxxxxxx>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
(no changes since v1)
drivers/net/usb/r8152.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 0c13d9950cd8..482957beae66 100644
--- 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;
--
2.42.0.582.g8ccd20d70d-goog
