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From: Antti Palosaari <crope@iki.fi>
To: Devin Heitmueller <dheitmueller@kernellabs.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>,
	Linux Media Mailing List <linux-media@vger.kernel.org>,
	Mauro Carvalho Chehab <m.chehab@samsung.com>
Subject: Re: [PATCH RFC v3 6/7] rtl2832_sdr: convert to SDR API
Date: Thu, 19 Dec 2013 20:38:28 +0200	[thread overview]
Message-ID: <52B33D24.1060705@iki.fi> (raw)
In-Reply-To: <CAGoCfiz1kWHXPC-b-Exw=AYrNeOzaCgSvr3+zLuf12g5gyYJxA@mail.gmail.com>

On 19.12.2013 18:59, Devin Heitmueller wrote:
>> I haven't
>> looked situation more carefully yet, but one thing that must be done at the
>> very first is to add some lock to prevent only DVB or V4L2 API could access
>> the hardware at time.
>
> Probably worth mentioning that we have *lots* of devices that suffer
> from this problem.  Our general tact has to been to do nothing and let
> the driver crash and burn in non-predictable ways when userland tries
> to use both APIs at the same time.
>
> So while it's pretty pathetic that we still haven't resolved this
> after all these years, if you didn't address the issue in the initial
> release then you wouldn't be much worse off than lots of other
> devices.

I think I could add some lock quite easily. I remember when I 
implemented cxd2820r DVB-T/T2/C demod driver and at the time it 
implements 2 frontends, one for DVB-T/T2 and one for DVB-C. I used 
shared lock to prevent access only for single fe at time. I think same 
solution works in that case too.

regards
Antti

-- 
http://palosaari.fi/

  reply	other threads:[~2013-12-19 18:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-16 22:08 [PATCH RFC v3 0/7] SDR API Antti Palosaari
2013-12-16 22:08 ` [PATCH RFC v3 1/7] v4l: add new tuner types for SDR Antti Palosaari
2013-12-17  7:31   ` Hans Verkuil
2013-12-16 22:08 ` [PATCH RFC v3 2/7] v4l: 1 Hz resolution flag for tuners Antti Palosaari
2013-12-17  7:31   ` Hans Verkuil
2013-12-16 22:08 ` [PATCH RFC v3 3/7] v4l: add stream format for SDR receiver Antti Palosaari
2013-12-17  7:32   ` Hans Verkuil
2013-12-16 22:08 ` [PATCH RFC v3 4/7] v4l: define own IOCTL ops for SDR FMT Antti Palosaari
2013-12-17  7:32   ` Hans Verkuil
2013-12-16 22:08 ` [PATCH RFC v3 5/7] v4l: enable some IOCTLs for SDR receiver Antti Palosaari
2013-12-17  7:34   ` Hans Verkuil
2013-12-17 16:40     ` Antti Palosaari
2013-12-18  7:32       ` Hans Verkuil
2013-12-16 22:08 ` [PATCH RFC v3 6/7] rtl2832_sdr: convert to SDR API Antti Palosaari
2013-12-17  7:45   ` Hans Verkuil
2013-12-19  9:21   ` Hans Verkuil
2013-12-19 16:50     ` Antti Palosaari
2013-12-19 16:59       ` Devin Heitmueller
2013-12-19 18:38         ` Antti Palosaari [this message]
2013-12-19 19:12           ` Devin Heitmueller
2013-12-16 22:08 ` [PATCH RFC v3 7/7] msi3101: " Antti Palosaari
2013-12-17  7:36 ` [PATCH RFC v3 0/7] " Hans Verkuil
2013-12-17 16:46   ` Antti Palosaari

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