RE: FEC driver hangs hardware on i.MX6SX

Hi, Shawn,

-----Original Message-----
From: Shawn Guo [mailto:shawn.guo@freescale.com]
Sent: Sunday, July 20, 2014 10:58 AM
To: Duan Fugang-B38611
Cc: Li Frank-B20596; David S. Miller; Guo Shawn-R65073;
netdev@vger.kernel.org; linux-arm-kernel@lists.infradead.org
Subject: FEC driver hangs hardware on i.MX6SX

Hi Fugang,

Your commit e8fcfcd5684a (net: fec: optimize the clock management to save
power) landed on mainline with v3.16-rc1.  It causes a hardware hang on
i.MX6SX, if the rootfs is not on NFS but something else like MMC.

I think the cause is that PTP is still accessing registers after FEC
driver calls fec_enet_clk_enable(ndev, false) to disable FEC clocks.
Can you please try to provide a fix for this regression soon?

Yes, you analyze is right. We had the related patch on internal trees since imx6sx bringup.
I will try to move the patch to upstream.

Thanks,
Andy