Davicom DM9000A regression

Davicom DM9000A regression

[Nikita Kiryanov]

Hi all.

I've encountered a connectivity problem with Davicom DM9000A chip.
The symptoms are the following message when booting via NFS:
dm9000 dm9000.0: eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

A bit of digging revealed the cause as this patch:
"DM9000B: driver initialization upgrade"
and specifically, the following line that was added by it:
dm9000_phy_write(dev, 0, MII_BMCR, BMCR_RESET); /* PHY RESET */
(uncommenting this line solves the problem).
Adding a delay after the phy reset did not help.

I'll appreciate any insight someone might have on this issue.

-- 
Regards,
Nikita.

Re: Davicom DM9000A regression

[Francois Romieu]

Nikita Kiryanov <nikita@compulab.co.il> :
[...]
> A bit of digging revealed the cause as this patch:
> "DM9000B: driver initialization upgrade"

(aka 6741f40d198c6a5feb23653a1efd4ca47f93d83d)

> and specifically, the following line that was added by it:
> dm9000_phy_write(dev, 0, MII_BMCR, BMCR_RESET); /* PHY RESET */
> (uncommenting this line solves the problem).
> Adding a delay after the phy reset did not help.

(I have no idea why Davicom enforced a dsp phy register write everywhere
instead of using db->type to identify the specific chipset revision that
requires it)

The last version of the patch changed - not much - without notice and
it did not contain the "tested on DM9000{A, B, E}, x86, arm" part.

You may try http://marc.info/?l=linux-netdev&m=136443908225335 to
see if it behaves the same.

-- 
Ueimor

Re: Davicom DM9000A regression

[Nikita Kiryanov]

On 06/12/2013 04:39 PM, Nikita Kiryanov wrote:
> Hi all.
>
> I've encountered a connectivity problem with Davicom DM9000A chip.
> The symptoms are the following message when booting via NFS:
> dm9000 dm9000.0: eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

Eh, copy pasted the wrong thing.
The message is a link down message:
dm9000 dm9000.0: eth0: link down

Also, CC-ing David Miller

-- 
Regards,
Nikita.

Re: Davicom DM9000A regression

[Nikita Kiryanov]

Hi Francois Romie,

On 06/13/2013 12:23 AM, Francois Romieu wrote:
> Nikita Kiryanov <nikita@compulab.co.il> :
[...]
> The last version of the patch changed - not much - without notice and
> it did not contain the "tested on DM9000{A, B, E}, x86, arm" part.
>
> You may try http://marc.info/?l=linux-netdev&m=136443908225335 to
> see if it behaves the same.
>

I gave it a try and the problem persists. Not surprising since it does
have the offending phy reset.

-- 
Regards,
Nikita.