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From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
	Mauro Carvalho Chehab <mchehab@infradead.org>
Subject: Re: [PATCH] Kconfig: disable Media Controller for DVB
Date: Fri, 12 Jun 2015 08:33:23 -0300	[thread overview]
Message-ID: <20150612083323.79562d10@recife.lan> (raw)
In-Reply-To: <557ABC28.2020101@xs4all.nl>

Em Fri, 12 Jun 2015 13:02:00 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> On 06/12/2015 12:57 PM, Mauro Carvalho Chehab wrote:
> > Since when we start discussions about the usage Media Controller
> > for complex hardware, one thing become clear: the way it is, MC
> > fails to map anything more complex than a webcam.
> > 
> > The point is that MC has entities named as devnodes, but the only
> > devnode used (before the DVB patches) is MEDIA_ENT_T_DEVNODE_V4L.
> > Due to the way MC got implemented, however, this entity actually
> > doesn't represent the devnode, but the hardware I/O engine that
> > receives data via DMA.
> > 
> > By coincidence, such DMA is associated with the V4L device node
> > on webcam hardware, but this is not true even for other V4L2
> > devices. For example, on USB hardware, the DMA is done via the
> > USB controller. The data passes though a in-kernel filter that
> > strips off the URB headers. Other V4L2 devices like radio may not
> > even have DMA. When it have, the DMA is done via ALSA, and not
> > via the V4L devnode.
> > 
> > In other words, MC is broken as a hole, but tagging it as BROKEN
> 
> hole -> whole
> 
> One of these days you'll have retrained your brain for this :-)

Heh ;)

> 
> > right now would do more harm than good.
> > 
> > So, instead, let's mark, for now, the DVB part as broken and
> > block all new changes to it while we don't fix this mess, with
> 
> "while we fix this mess, which"

Changed to:
   "block all new changes to MC while we fix this mess, which"


Sending version 2.

Regards,
Mauro

  reply	other threads:[~2015-06-12 11:33 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-12 10:57 [PATCH] Kconfig: disable Media Controller for DVB Mauro Carvalho Chehab
2015-06-12 11:02 ` Hans Verkuil
2015-06-12 11:33   ` Mauro Carvalho Chehab [this message]
  -- strict thread matches above, loose matches on Subject: below --
2015-06-15 12:29 Mauro Carvalho Chehab
2015-06-16  9:26 Mauro Carvalho Chehab

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