On 28/07/2017 20:56, Måns Rullgård wrote:
> Marc Gonzalez writes:
>
>> On 28/07/2017 18:17, Måns Rullgård wrote:
>>
>>> Marc Gonzalez wrote:
>>>
>>>> ndo_stop breaks RX in a way that ndo_open is unable to undo.
>>>
>>> Please elaborate. Why can't it be fixed in a less heavy-handed way?
>>
>> I'm not sure what "elaborate" means. After we've been through
>> ndo_stop once, the board can send packets, but it doesn't see
>> any replies from remote systems. RX is wedged.
>
> So you say, but you have not explained why this happens. Until we know
> why, we can't decide on the proper fix.
I'll try adding delays in strategic places, and see if
I can trigger the same bug on tango4. If I can't, then
this work around is all we've got.
And I need nb8800_init for resume anyway, so I might
as well use it in ndo_open.
TODO: test power savings from holding HW in reset.
>> I think ndo_stop is rare enough an event that doing a full
>> reset is not an issue, in terms of performance.
>
> Performance isn't the issue. Doing the right thing is.
I don't have always have time to figure out exactly how
broken HW is broken. It's already bad enough that disabling
DMA requires sending a fake packet through the loop back...
>>> I'm pretty sure this doesn't preserve everything it should.
>>
>> Hmmm, we're supposed to start fresh ("full reset").
>> What could there be to preserve?
>> You mentioned flow control and multicast elsewhere.
>> I will take a closer look. Thanks for the heads up.
>
> Yes, those settings are definitely lost with your patch. Now I'm not
> sure whether the networking core expects these to survive a stop/start
> cycle, so please check that. There might also be other less obvious
> things that need to be preserved.
The original code calls nb8800_pause_config() every
time the link comes up. The proposed patch doesn't
change that.
Regards.
