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From: Hans Verkuil <hverkuil@xs4all.nl>
To: Florian Echtler <floe@butterbrot.org>
Cc: linux-media@vger.kernel.org, linux-input@vger.kernel.org, modin@yuri.at
Subject: Re: [PATCH 4/5] add V4L2 control functions
Date: Mon, 5 Feb 2018 22:40:10 +0100	[thread overview]
Message-ID: <a968db4a-bce8-423b-ccca-d9a613acec99@xs4all.nl> (raw)
In-Reply-To: <alpine.DEB.2.10.1802052234090.18874@butterbrot>

On 02/05/2018 10:36 PM, Florian Echtler wrote:
> Hello Hans,
> 
> On Mon, 5 Feb 2018, Hans Verkuil wrote:
>> On 02/05/2018 03:29 PM, Florian Echtler wrote:
>>> +
>>> +static int sur40_vidioc_queryctrl(struct file *file, void *fh,
>>> +			       struct v4l2_queryctrl *qc)
>>
>> Sorry, but this is very wrong. Use the control framework instead. See
>> https://hverkuil.home.xs4all.nl/spec/kapi/v4l2-controls.html and pretty much all
>> media drivers (with the exception of uvc). See for example this driver:
>> drivers/media/pci/tw68/tw68-video.c (randomly chosen).
>>
>> It actually makes life a lot easier for you as you don't have to perform any
>> range checks and all control ioctls are automatically supported for you.
> 
> thanks for the quick reply, I wasn't aware of that framework at all :-) 
> Will certainly use it.
> 
> What's the earliest kernel version this is supported on, in case we want 
> to backport this for our standalone module, too?

Initial commit was in August 2010, so it's been around for quite some time :-)

Regards,

	Hans

  reply	other threads:[~2018-02-05 21:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-05 14:29 [PATCH 0/5] [RFC] add video controls to SUR40 driver Florian Echtler
2018-02-05 14:29 ` [PATCH 1/5] add missing blob structure tag field Florian Echtler
2018-02-05 14:29 ` [PATCH 2/5] add video control register definitions Florian Echtler
2018-02-05 14:29 ` [PATCH 3/5] add video control register handlers Florian Echtler
2018-02-05 14:29 ` [PATCH 4/5] add V4L2 control functions Florian Echtler
2018-02-05 14:54   ` Hans Verkuil
2018-02-05 21:36     ` Florian Echtler
2018-02-05 21:40       ` Hans Verkuil [this message]
2018-02-05 14:29 ` [PATCH 5/5] add default control values as module parameters Florian Echtler
2018-02-05 14:56   ` Hans Verkuil
2018-02-06  9:18     ` Florian Echtler

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