Re: [PATCH net v2 2/7] net: dsa: mt7530: fix trapping frames with multiple CPU ports on MT7530

[Arınç ÜNAL]

On 13.06.2023 21:29, Russell King (Oracle) wrote:
> On Tue, Jun 13, 2023 at 08:58:33PM +0300, Arınç ÜNAL wrote:
> > On 13.06.2023 20:39, Vladimir Oltean wrote:
> > > On Tue, Jun 13, 2023 at 08:30:28PM +0300, Arınç ÜNAL wrote:
> > > > That fixes port 5 on certain variants of the MT7530 switch, as it was
> > > > already working on the other variants, which, in conclusion, fixes port 5 on
> > > > all MT7530 variants.
> > >
> > > Ok. I didn't pay enough attention to the commit message.
> > >
> > > > And no, trapping works. Having only CPU port 5 defined on the devicetree
> > > > will cause the CPU_PORT bits to be set to port 5. There's only a problem
> > > > when multiple CPU ports are defined.
> > >
> > > Got it. Then this is really not a problem, and the commit message frames
> > > it incorrectly.
> >
> > Actually this patch fixes the issue it describes. At the state of this
> > patch, when multiple CPU ports are defined, port 5 is the active CPU port,
> > CPU_PORT bits are set to port 6.
>
> Maybe it's just me being dumb, but I keep finding things difficult to
> understand, such as the above paragraph.
>
> It sounds like you're saying that _before_ this patch, port 5 is the
> active CPU port, but the CPU_PORT *FIELD* NOT BITS are set such that
> port 6 is the active CPU port. Therefore, things are broken, and this
> patch fixes it.

Yes, CPU_PORT field, and yes this patch fixes the issue by setting the 
field to 5 when multiple CPU ports are used. Because before this patch, 
the active CPU port is 5. The CPU_PORT field must match this.

> Or are you saying that after this patch is applied, port 5 is the
> active CPU port, but the CPU_PORT *FIELD* is set to port 6. If that's
> true, then I've no idea what the hell is going on here because it
> seems to be senseless.

No, when the "prefer port 6" patch is applied, the active CPU port will 
be port 6.

The CPU_PORT field will always be set to 6, regardless of "net: dsa: 
mt7530: fix trapping frames with multiple CPU ports on MT7530". 
Therefore, the "prefer port 6" patch makes "net: dsa: mt7530: fix 
trapping frames with multiple CPU ports on MT7530" redundant.

"net: dsa: mt7530: fix trapping frames with multiple CPU ports on 
MT7530" becomes important after the changing the DSA conduit support is 
introduced.

> I think at this point I just give up trying to understand what the
> hell these patches are trying to do - in my opinion, the commit
> messages are worded attrociously and incomprehensively.

If that's how you feel, you can tune in to v5 where I will address the 
patch logs.

Arınç