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From: James Liao <jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
To: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	Kevin Hilman <khilman-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
	Matthias Brugger
	<matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 2/4] soc: mediatek: Init MT8173 scpsys driver earlier
Date: Thu, 31 Dec 2015 13:59:26 +0800	[thread overview]
Message-ID: <1451541566.10610.10.camel@mtksdaap41> (raw)
In-Reply-To: <6145950.8rtkDup7QD@wuerfel>

Hi Arnd,

On Wed, 2015-12-30 at 11:35 +0100, Arnd Bergmann wrote:
> On Wednesday 30 December 2015 18:12:08 James Liao wrote:
> > On Wed, 2015-12-30 at 09:52 +0100, Arnd Bergmann wrote:
> > > On Wednesday 30 December 2015 14:41:44 James Liao wrote:
> > > > Some power domain comsumers may init before module_init.
> > > > So the power domain provider (scpsys) need to be initialized
> > > > earlier too.
> > > > 
> > > > Signed-off-by: James Liao <jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > > > ---
> > > > 
> > > 
> > > Why?
> > 
> > Some drivers use different init level to ensure they can be initialized
> > before other drivers. To support these drivers, moving scpsys driver's
> > initial function to subsys_init is the most easy way.
> 
> This is just the same generic explanation that you already have.
> 
> Please be more specific what the dependency is and why we can't rely
> on deferred probing here.

In our case, there is a SMI driver provide APIs to control multiple
devices that attached to different power domains.Video encoder / decoder
and GPU drivers are SMI users. It's not easy for SMI users to detect SMI
and scpsys driver are initialized or not. A most easy way to resolve the
init sequence issue is moving SMI and scpsys driver in early init stage.

Do you prefer to keep scpsys driver's init in module_init? If yes, I can
remove this patch in next version.


Best regards,

James

  reply	other threads:[~2015-12-31  5:59 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-30  6:41 [PATCH 0/4] Mediatek MT2701 SCPSYS power domain support James Liao
     [not found] ` <1451457706-14798-1-git-send-email-jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-12-30  6:41   ` [PATCH 1/4] soc: mediatek: Separate scpsys driver common code James Liao
2015-12-30  8:52     ` Arnd Bergmann
2015-12-30 10:08       ` James Liao
2015-12-30  6:41   ` [PATCH 2/4] soc: mediatek: Init MT8173 scpsys driver earlier James Liao
     [not found]     ` <1451457706-14798-3-git-send-email-jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-12-30  8:52       ` Arnd Bergmann
2015-12-30 10:12         ` James Liao
2015-12-30 10:35           ` Arnd Bergmann
2015-12-31  5:59             ` James Liao [this message]
2015-12-31  9:16               ` James Liao
2015-12-31 14:45                 ` Arnd Bergmann
2016-01-04  2:52                   ` James Liao
2015-12-30  6:41   ` [PATCH 3/4] soc: mediatek: Add MT2701 power dt-bindings James Liao
2015-12-30  6:41   ` [PATCH 4/4] soc: mediatek: Add MT2701/MT7623 scpsys driver James Liao
     [not found]     ` <1451457706-14798-5-git-send-email-jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-12-30  9:01       ` Daniel Kurtz
2015-12-30 10:18         ` James Liao
2015-12-30 17:49           ` Matthias Brugger
2016-01-05  5:23             ` James Liao
2016-01-08 11:26               ` Matthias Brugger

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