[PATCH] netdev/fec: fix ifconfig eth0 down hang issue (v3)

Bryan Wu bryan.wu at canonical.com
Thu Apr 22 14:24:31 UTC 2010


On 04/22/2010 08:57 PM, Tim Gardner wrote:
> On 04/22/2010 12:16 AM, Bryan Wu wrote:
>> BugLink: http://bugs.launchpad.net/bugs/559065
>>
>> v3:
>> if fec_enet_mii_probe() fails, we should exit the open and resume
>> functions
>> properly and give up further operations without a proper PHY connected.
>>
>> v2:
>> Check fec_enet_mii_probe() return value directly, instead of fep->phy_dev
>>
>> v1:
>> In ethernet connection open/close function, we need to use phy_connect
>> and phy_disconnect operation before we start/stop phy. Otherwise it will
>> cause system hang. Also suspend/resume needs the same fix.
>>
>> Signed-off-by: Bryan Wu<bryan.wu at canonical.com>
>> ---
>> drivers/net/fec.c | 21 ++++++++++++++++++++-
>> 1 files changed, 20 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/net/fec.c b/drivers/net/fec.c
>> index 2280373..b14e4d5 100644
>> --- a/drivers/net/fec.c
>> +++ b/drivers/net/fec.c
>> @@ -929,7 +929,13 @@ fec_enet_open(struct net_device *dev)
>> return ret;
>>
>> /* schedule a link state check */
>> + ret = fec_enet_mii_probe(dev);
>> + if (!ret) {
>> + fec_enet_free_buffers(dev);
>> + return ret;
>> + }
>> phy_start(fep->phy_dev);
>> +
>> netif_start_queue(dev);
>> fep->opened = 1;
>> return 0;
>> @@ -942,10 +948,13 @@ fec_enet_close(struct net_device *dev)
>>
>> /* Don't know what to do yet. */
>> fep->opened = 0;
>> - phy_stop(fep->phy_dev);
>> netif_stop_queue(dev);
>> +
>> fec_stop(dev);
>>
>> + if (fep->phy_dev)
>> + phy_disconnect(fep->phy_dev);
>> +
>> fec_enet_free_buffers(dev);
>> clk_disable(fep->clk);
>>
>> @@ -1396,6 +1405,8 @@ fec_suspend(struct platform_device *dev,
>> pm_message_t state)
>> fep = netdev_priv(ndev);
>> if (netif_running(ndev)) {
>> netif_device_detach(ndev);
>> + if (fep->phy_dev)
>> + phy_disconnect(fep->phy_dev);
>> fec_stop(ndev);
>> clk_disable(fep->clk);
>> }
>> @@ -1409,12 +1420,20 @@ fec_resume(struct platform_device *dev)
>> {
>> struct net_device *ndev = platform_get_drvdata(dev);
>> struct fec_enet_private *fep;
>> + int ret;
>>
>> if (ndev) {
>> fep = netdev_priv(ndev);
>> if (netif_running(ndev)) {
>> clk_enable(fep->clk);
>> fec_restart(ndev, 1);
>> + ret = fec_enet_mii_probe(ndev);
>> + if (!ret) {
>> + fec_stop(ndev);
>> + clk_disable(fep->clk);
>> + return ret;
>> + }
>> + phy_start(fep->phy_dev);
>> netif_device_attach(ndev);
>> }
>> }
>
> One final comment. fec_enet_mii_probe() should set fep->phy_dev=NULL
> upon entry so that if it errors out fep->phy_dev is not left with a
> bogus value (which could happen in fec_resume()).
>

Yeah, good point. I will provide another patch to add this.

> How is the fsl-imx51 physically constructed wrt to the ethernet phy? Is
> it possible for the phy to disappear during a suspend/resume cycle?
>

Actually, FEC is an on-chip controller of imx51 and PHY is an external chip 
which connected to imx51 via MDIO and MII bus. Since suspend/resume operation is 
very similar to close/open thing here, I just wanna keep them similar.

Thanks,
-- 
Bryan Wu <bryan.wu at canonical.com>
Kernel Developer    +86.138-1617-6545 Mobile
Ubuntu Kernel Team | Hardware Enablement Team
Canonical Ltd.      www.canonical.com
Ubuntu - Linux for human beings | www.ubuntu.com




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