Date:   Mon, 3 Apr 2017 15:07:32 +0200
From:   Giuseppe CAVALLARO <peppe.cavallaro@...com>
To:     Joao Pinto <Joao.Pinto@...opsys.com>,
        Niklas Cassel <niklas.cassel@...s.com>,
        Thierry Reding <treding@...dia.com>,
        Corentin Labbe <clabbe.montjoie@...il.com>
CC:     David Miller <davem@...emloft.net>, <arnd@...db.de>,
        <alexandre.torgue@...com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [net-next] stmmac: use netif_set_real_num_{rx,tx}_queues

Hello Joao

On 3/30/2017 6:42 PM, Joao Pinto wrote:
> Às 5:35 PM de 3/30/2017, Niklas Cassel escreveu:
>> On 03/30/2017 04:34 PM, Thierry Reding wrote:
>>> On Thu, Mar 30, 2017 at 09:45:36AM +0200, Corentin Labbe wrote:
>>>> On Tue, Mar 28, 2017 at 06:01:05PM -0700, David Miller wrote:
>>>>> From: Arnd Bergmann <arnd@...db.de>
>>>>> Date: Tue, 28 Mar 2017 11:48:21 +0200
>>>>>
>>>>>> A driver must not access the two fields directly but should instead use
>>>>>> the helper functions to set the values and keep a consistent internal
>>>>>> state:
>>>>>>
>>>>>> ethernet/stmicro/stmmac/stmmac_main.c: In function 'stmmac_dvr_probe':
>>>>>> ethernet/stmicro/stmmac/stmmac_main.c:4083:8: error: 'struct net_device' has no member named 'real_num_rx_queues'; did you mean 'real_num_tx_queues'?
>>>>>>
>>>>>> Fixes: a8f5102af2a7 ("net: stmmac: TX and RX queue priority configuration")
>>>>>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>>>>> Applied.
>>>> This break my revert patch. (since it patch ("net: stmmac: enable multiple buffers").
>>>> Since dwmac-sunxi is still broken, what can I do ? send two revert patch ? or adapt the reverting patch.
>>> Have you tried if the kcalloc() patch I sent on Tuesday fixes things the
>>> issues introduced by the multiple buffers patch? Niklas reported that it
>>> restores functionality on his setup.
>>>
>>> If it makes things work for you as well, we could maybe avoid the revert
>>> altogether.
>> Thierry, I know that you are using DWMAC CORE 4.XX
>> How many RX queues and how many TX queues have you got?
>>
>> I'm also using DWMAC CORE 4.XX
>> We have 2 TX queues and 1 RX queue.
>>
>> I think that Corentin is using DWMAC CORE 3.XX
>>
>> I know that Joao is using an IP Prototyping Kit that uses
>> DWMAC CORE 4.XX (connected via PCIe).
>> It would be nice if Joao could get an IP Prototyping Kit
>> based on DWMAC CORE 3.XX.
>>
>> Doesn't Synopsys have an IP Prototyping Kit based on
>> DWMAC CORE 3.XX laying around somewhere? :)
>>
> I requested a prototyping platform with MAC 100 or a MAC 1000 in order to make
> more tests, but I don't have an ETA for it yet.
>
> The implication of the multiple buffers patch in 3.xx is some flow change in the
> configuration of dma op mode or similar. I would recomend Corentin to dump the
> dma & mac registers in the end of the _open function in order to see if the DMA
> is really being well configured and is really started.

Old devices managed as stmmac: mac10/100 platform driver have no 
multi-queue support.

It was introduced in the new versions managed by mac1000 but in my opinion
the stmmac driver has to only work with a single queue for tx and rx on ALL
the 3.x versions.

In fact, although the latest series have the multi-queue and channels 
there is
just one IRQ and this is a very poor implementation.
The 3.xx is very different from what we have in the 4.XX (QoS) on this 
part and AV/B.

Nobody has ever asked for having this support in all these years for the 
previous
chips.

Adding this kind of support we'll spend time for having a no useful 
optimization
and risking to break the compatibility with a lot platforms that use 
these chips.

I image, multi-queue stable on 4.XX and no support on all older versions.
Let me know if you share that.

Regards
Peppe

>
> Thanks.
>
> Joao
>
>

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