[U-Boot] [linux-sunxi] Re: [PATCH] sunxi: Fix gmac not working reliable on the Bananapi

jonsmirl at gmail.com jonsmirl at gmail.com
Tue Sep 30 14:26:53 CEST 2014

On Tue, Sep 30, 2014 at 8:02 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
> On 09/29/2014 08:35 PM, jonsmirl at gmail.com wrote:
>> On Mon, Sep 29, 2014 at 2:16 PM, Karsten Merker <merker at debian.org> wrote:
>>> On Mon, Sep 29, 2014 at 09:13:37AM +0300, Siarhei Siamashka wrote:
>>>> How did you come to the idea to poke these bits?
>>> The linux 3.4 kernel from https://github.com/LeMaker/linux-bananapi
>>> (which is a patched linux-sunxi.org 3.4 kernel) does not show this
>>> problem, so we started looking into what is different there, and the
>>> relevant change that was found was setting these particular
>>> undocumented bits.
>> File at issue here asking for the documentation
>> https://github.com/allwinner-zh/documents
> I'm already talking to Allwinner about this, it seems that bits
> 10-11, or more likely 10-12 of the gmac clk register are the tx
> equivalent of bits 5-7, "Configure GMAC receive clock delay
> chain". I think this is there to deal with the pcb data and clk
> traces not having the same length, so that this is highly board
> specific. I'm waiting on confirmation on this from Allwinner,
> as well as some info on the unit of this 0-7 value.

Encourage them to update the manual and push a new copy to git hub
immediately. Too much info like this is getting buried in mail
archives. Electronic publishing is free - update as often as you want.

The more they fix stuff like this in the manual, the fewer questions
they will need to deal with in person. When it goes into the manual it
won't get lost.

> Regards,
> Hans

Jon Smirl
jonsmirl at gmail.com

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