Re: [PATCH] soundwire: debugfs: use controller id instead of link_id

[Srinivas Kandagatla]

On 19/01/2021 15:54, Pierre-Louis Bossart wrote:
> On 1/19/21 8:52 AM, Vinod Koul wrote:
> > On 15-01-21, 16:25, Srinivas Kandagatla wrote:
> > > link_id can be zero and if we have multiple controller instances
> > > in a system like Qualcomm debugfs will end-up with duplicate namespace
> > > resulting in incorrect debugfs entries.
> > >
> > > Using id should give a unique debugfs directory entry and should fix 
> > > below
> > > warning too.
> > > "debugfs: Directory 'master-0' with parent 'soundwire' already present!"
> >
> > Yeah id is guaranteed to be unique so this will work.
> >
> > Applied, thanks
>
> This patch is a no-op for Intel, but I am not convinced it's the right 
> fix or the definitions are not consistent.

It depends if the intention is to represent full Hierarchy in debugfs, 
then I agree. Its was consistent even before!

currently we have
/sys/kernel/debug/soundwire/master-*

Are you suggesting that we have something like this:

/sys/kernel/debug/soundwire/xyz-controller/master-<LINK-ID> ??
/sys/kernel/debug/soundwire/xyz-controller/master-<LINK-ID>/xyz-slave/master-<LINK-ID> 
??


Or may be something much simpler like:

/sys/kernel/debug/soundwire/master-<ID>.<LINK_ID>


--srini

>   * @link_id: Link id number, can be 0 to N, unique for each Master
>   * @id: bus system-wide unique id
>
> In the MIPI/DisCo definitions, a controller can have multiple masters. 
> if you have multiple controllers, each of them should have their own 
> debugfs directory IMHO. It's totally fine to have multiple bus/masters 
> with a link_id == 0.