Re: [5/6] mvneta: implement SGMII-based in-band link state signaling

Hi Stas,

On Fri, 27 Mar 2015, Stas Sergeev wrote:

When MDIO bus is unavailable (common setup for SGMII), the in-band
signaling must be used to correctly track link state.
This patch enables the in-band status delivery and interrupts for
links state changes, namely:
- link up/down
- link speed
- duplex full/half
Upon reciving the appropriate interrupt, the driver updates the
fixed_phy status to match the received status.

I'm seeing a regression with this patch when trying to netboot an Armada
XP board (by reverting this commit it is fine), the network
link stays down:

[    9.274492] mvneta d0070000.ethernet eth0: Link is Down

(I've added an extra call to phy_print_status() in mvneta_adjust_link() to
get this trace).

I've tried to dig a bit in the code, and it seems that the status.link flag
never gets set in mvneta_fixed_link_update(). If I try to force the
use_inband_status to 0 in mvneta_probe(), it boots properly so I'm not
sure that I need the in-band status/delivery in my case ; I'm using a
custom DTB with a fixed-link:

eth0: ethernet@70000 {
         status = "okay";
         fixed-link = <1 1 1000 0 0>;
         phy-mode = "sgmii";
};

Could there be something missing in the condition that initializes
pp->use_inband_status?

PS: I've also tried to apply this patch without success:
https://lkml.org/lkml/2015/6/18/496

-- 
Sébastien