Re: [PATCH] [net-next] stmmac: use netif_set_real_num_{rx,tx}_queues

[Giuseppe CAVALLARO]

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@xxxxxxxx>
> > > > > 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@xxxxxxxx>
> > > > > 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