Re: [PATCH v2] sound: pci: ctxfi: pr_* replaced with dev_*

From: Sudip Mukherjee
Date: Thu Sep 18 2014 - 05:21:48 EST


On Mon, Sep 15, 2014 at 08:17:52PM +0200, Takashi Iwai wrote:
> At Mon, 15 Sep 2014 20:55:54 +0530,
> Sudip Mukherjee wrote:
> >
> > On Mon, Sep 15, 2014 at 04:29:48PM +0200, Takashi Iwai wrote:
> > > At Mon, 15 Sep 2014 19:39:41 +0530,
> > > Sudip Mukherjee wrote:
<snip>
> > > >
> > > > diff --git a/sound/pci/ctxfi/ctresource.c b/sound/pci/ctxfi/ctresource.c
> > > > index e49d2be..80beecb 100644
> > > > --- a/sound/pci/ctxfi/ctresource.c
> > > > +++ b/sound/pci/ctxfi/ctresource.c
> > > (snip)
> > > > @@ -282,8 +287,9 @@ int rsc_mgr_uninit(struct rsc_mgr *mgr)
> > > > case SUM:
> > > > break;
> > > > default:
> > > > - pr_err("ctxfi: Invalid resource type value %d!\n",
> > > > - mgr->type);
> > > > + dev_err(&(((struct hw *)mgr->hw)->pci->dev),
> > > > + "ctxfi: Invalid resource type value %d!\n",
> > > > + mgr->type);
> > >
> > > Did you really conclude that this is the best way?
> > > Also, is it good to mix up the usages of both card->dev and &pci->dev?
> > > Think again.
> > >
> >
> > i have a doubt regarding this :-
> > in the snd_card_new() card->dev is being assigned with &pci->dev ,
> > then are not they the same ?
>
> Yes, but how can it be guaranteed in future? We may avoid the
> problems in future by keeping the consistency at this moment. It's
> one of the good points of keeping code consistent, in addition to:
> increased readability / understandability and making the bug easier to
> be spotted.

understood the point.
>
> > i was trying to get some way of finding out the reference of card->dev from the resource manager ,
> > but ... :(
> > i will try again and if i cant find any way i will ask for some hint from you.
>
> Good! A hint is that there is no 100% perfect way to achieve this.
> It's always compromise, and you'll have to choose which one is better
> than others. For that, you'll have to evaluate multiple
> implementations, and it's a really good exercise for coding.
>

i can find the rsc_mgr from the snd_card or ct_atc
but if i want to find the reference to the device from the managers , then
either i can go with
1) &(((struct hw *)mgr->hw)->pci->dev)
or
2) use pci_get_drvdata with ((struct hw *)mgr->hw)->pci
or
3) using container_of with &(((struct hw *)mgr->hw)->pci->dev) to find the pointer to snd_card via card_dev , but it becomes too complicated :(

we can get to all the managers (rsc_mgr, amixer_mgr, src_mgr ...) using atc->rsc_mgrs[] , then there should be some simple way to go
the opposite way (reaching atc from the managers) . container_of will not work .. :(
or am i missing something??

thanks
sudip


> > i am still a newbie , and started this pr_* to dev_* on your inspiration , and i hope
> > you will not be irritated by my patches . :)
>
> No problem. I left these driver codes just because of laziness, as I
> knew to work more on the code than the simple scripting :)
>
>
> Takashi
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