From mboxrd@z Thu Jan  1 00:00:00 1970
From: daniel@ffwll.ch (Daniel Vetter)
Date: Mon, 19 Oct 2015 16:42:25 +0200
Subject: [RFC PATCH v2 1/4] drm: Introduce generic probe function for
 component based masters.
In-Reply-To: <20151019132638.GB32532@n2100.arm.linux.org.uk>
References: <1445257313-7147-1-git-send-email-Liviu.Dudau@arm.com>
 <1445257313-7147-2-git-send-email-Liviu.Dudau@arm.com>
 <20151019122537.GZ32532@n2100.arm.linux.org.uk>
 <20151019130258.GU3394@e106497-lin.cambridge.arm.com>
 <20151019132638.GB32532@n2100.arm.linux.org.uk>
Message-ID: <20151019144225.GE13786@phenom.ffwll.local>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Oct 19, 2015 at 02:26:38PM +0100, Russell King - ARM Linux wrote:
> On Mon, Oct 19, 2015 at 02:02:58PM +0100, Liviu Dudau wrote:
> > On Mon, Oct 19, 2015 at 01:25:37PM +0100, Russell King - ARM Linux wrote:
> > > Please don't move this into here, it's completely inappropriate.  Just
> > > because something makes use of this does not mean they only support
> > > 32-bit DMA.  Besides, this has nothing to do with whether or not it's
> > > OF-based or not.
> > 
> > Understood. My thinking process was that component-based drivers are all
> > OF-enabled (how else do you make use of the framework?) and 32-bit DMA is
> > present in 2 out of 3 drivers that are converted, so it looks to be common
> > enough that adding it to armada would not hurt. It was all done in the name of
> > collecting common code in a single function.
> 
> Which is an utterly crap reason.
> 
> It's also not appropriate.  I'm really not sure why you think that moving
> this here would in any way be appropriate - from my point of view, the
> mere proposal is utterly insane.
> 
> The "container" device does not do any DMA, so it's inappropriate for
> it to have DMA masks set or negotiated on it.  So, actually, no one
> should be setting the DMA mask for their container device.  It's wrong.

I think (and my opinion doesn't carry as much wheight here on dri-devel
than intel-gfx) the above is over the top bashing of a new contributor to
drm who really seems trying to do right. I think that's unecessary,
especially since you follow up with the reasonable reply below.

Thanks, Daniel

> What if we have a 64-bit OF based platform wanting to use the component
> helper, and they want to call this function?  You prevent them doing so
> by moving this into here, because they're then forced down to 32-bit DMA.
> Please, get rid of it, and leave this crappiness in the respective
> drivers.
> 
> -- 
> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> according to speedtest.net.

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch