Ubiquiti loco xw eth0 bug

Bug description

Some Ubiquiti loco xw have a hardware bug which results in an interface shutdown with now possibility to bring the interface without reboot. More details, see https://dev.openwrt.org/ticket/19085

Steps for building workaround

Find a way to detect hang of eth0

In general there are two places where uid of PHY is printed.

1. ag71xx_phy.c

   function: static int ag71xx_phy_connect_multi(struct ag71xx *ag)   
   ....
   DBG("%s: PHY found at %s, uid=%08x\n",                                                                  
                           dev_name(dev),                                                                                  
                           dev_name(&ag->mii_bus->phy_map[phy_addr]->dev),                                                 
                           ag->mii_bus->phy_map[phy_addr]->phy_id);  
  
   dev_info(dev, "connected to PHY at %s [uid=%08x, driver=%s]\n",                                                 
                       dev_name(&phydev->dev), phydev->phy_id, phydev->drv->name); 

2. ag71xx_main.c

 void ag71xx_link_adjust(struct ag71xx *ag)
   ....
   struct device *dev = &ag->pdev->dev; 
   struct ag71xx_platform_data *pdata = ag71xx_get_pdata(ag);                                                      
           struct phy_device *phydev = NULL;                                                                               
           int phy_addr;                                                                                                   
           int ret = 0;
  
   for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++) {                                                       
                   if (!(pdata->phy_mask & (1 << phy_addr)))                                                               
                           continue;                                                                                       
                                                                                                                           
                   if (ag->mii_bus->phy_map[phy_addr] == NULL)                                                             
                           continue;                                                                                       
                                                                                                                           
                   DBG("%s: PHY found at %s, uid=%08x\n",                                                                  
                           dev_name(dev),                                                                                  
                           dev_name(&ag->mii_bus->phy_map[phy_addr]->dev),                                                 
                           ag->mii_bus->phy_map[phy_addr]->phy_id);                                                        
                                                                                                                           
                  if (phydev == NULL)                                                                                     
                           phydev = ag->mii_bus->phy_map[phy_addr];                                                        
    } 
  
   dev_info(dev, "connected to PHY at %s [uid=%08x, driver=%s]\n",                                                 
                       dev_name(&phydev->dev), phydev->phy_id, phydev->drv->name); 

ID can be read in ag71xx_link_adjust() in file ag71xx_main.c. See http://pastebin.com/0ze9iFcb for an example. But the ID is not changing when eth0 hangs. The output when it hangs is:

[155921.360000] ag71xx ag71xx.0: connected to PHY at ag71xx-mdio.0:01 [uid=004dd023, driver=Generic PHY] (Opennet-Info1)
[155921.360000] eth0: link up (10Mbps/Half duplex)
[155923.370000] ag71xx ag71xx.0: connected to PHY at ag71xx-mdio.0:01 [uid=004dd023, driver=Generic PHY] (Opennet-Info1)
[155923.370000] eth0: link down
[155923.380000] br-lan: port 1(eth0) entered disabled state

Next try: Use another patch from Till...

Find a way to reset eth0

...TODO...