[PATCH v2 1/2] net: usb: ax88179_178a: fix failed operations during ax88179_reset

[Jose Ignacio Tornos Martinez]

Using generic ASIX Electronics Corp. AX88179 Gigabit Ethernet device,
the following test cycle has been implemented:
    - power on
    - check logs
    - shutdown
    - after detecting the system shutdown, disconnect power
    - after approximately 60 seconds of sleep, power is restored
Running some cycles, sometimes error logs like this appear:
    kernel: ax88179_178a 2-9:1.0 (unnamed net_device) (uninitialized): Failed to write reg index 0x0001: -19
    kernel: ax88179_178a 2-9:1.0 (unnamed net_device) (uninitialized): Failed to read reg index 0x0001: -19
    ...
These failed operation are happening during ax88179_reset execution, so
the initialization could not be correct.

In order to avoid this, we need to increase the delay after reset and
clock initial operations. By using these larger values, many cycles
have been run and no failed operations appear.

It would be better to check some status register to verify when the
operation has finished, but I do not have found any available information
(neither in the public datasheets nor in the manufacturer's driver). The
only available information for the necessary delays is the maufacturer's
driver (original values) but the proposed values are not enough for the
tested devices.

Fixes: e2ca90c276e1f ("ax88179_178a: ASIX AX88179_178A USB 3.0/2.0 to gigabit ethernet adapter driver")
Reported-by: Herb Wei <weihao.bj@xxxxxxxxxxxxx>
Tested-by: Herb Wei <weihao.bj@xxxxxxxxxxxxx>
Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@xxxxxxxxxx>
---
V1 -> V2:
- Add Fixes tag.
- Comments about the available information and manufacturer's driver
  reference to complete why the new values are needed.

 drivers/net/usb/ax88179_178a.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
index aff39bf3161d..4ea0e155bb0d 100644
--- a/drivers/net/usb/ax88179_178a.c
+++ b/drivers/net/usb/ax88179_178a.c
@@ -1583,11 +1583,11 @@ static int ax88179_reset(struct usbnet *dev)
 
 	*tmp16 = AX_PHYPWR_RSTCTL_IPRL;
 	ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_PHYPWR_RSTCTL, 2, 2, tmp16);
-	msleep(200);
+	msleep(500);
 
 	*tmp = AX_CLK_SELECT_ACS | AX_CLK_SELECT_BCS;
 	ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_CLK_SELECT, 1, 1, tmp);
-	msleep(100);
+	msleep(200);
 
 	/* Ethernet PHY Auto Detach*/
 	ax88179_auto_detach(dev);
-- 
2.42.0