From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([85.220.165.71]:43975 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727132AbeGMLJD (ORCPT ); Fri, 13 Jul 2018 07:09:03 -0400 Date: Fri, 13 Jul 2018 12:54:47 +0200 From: Marco Felsch To: Javier Martinez Canillas Cc: Hans Verkuil , Mauro Carvalho Chehab , Niklas =?iso-8859-1?Q?S=F6derlund?= , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v2 2/2] v4l: Add support for STD ioctls on subdev nodes Message-ID: <20180713105447.73l6rx2bod7cpp3e@pengutronix.de> References: <20180517143016.13501-1-niklas.soderlund+renesas@ragnatech.se> <20180517143016.13501-3-niklas.soderlund+renesas@ragnatech.se> <20180705094421.0bad52e2@coco.lan> <2f4121bb-1774-410c-5425-f9977d38a02e@xs4all.nl> <7efd92ca-1891-4054-29d5-dca5813b37d6@redhat.com> <20180711103958.gd6szkgfljjnr44w@pengutronix.de> <94a592f4-a130-b210-a461-9a4f758164a8@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94a592f4-a130-b210-a461-9a4f758164a8@redhat.com> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Javier, On 18-07-13 11:18, Javier Martinez Canillas wrote: > On 07/11/2018 12:39 PM, Marco Felsch wrote: > > Hi Javier, > > > > On 18-07-08 15:11, Javier Martinez Canillas wrote: > >> [adding Marco Felsch since he has been working on this driver] > >> > >> On 07/05/2018 03:12 PM, Hans Verkuil wrote: > >>> On 05/07/18 14:44, Mauro Carvalho Chehab wrote: > >>>> Javier, > >>>> > >>>> How standard settings work with the current OMAP3 drivers with tvp5150? > >>> > >>> It looks like tvp5150 uses autodetect of the standard, which in general is > >> > >> That's correct, the driver uses standard autodetect. > >> > >>> not a good thing to do since different standards have different buffer > >>> sizes. But this chip can scale, so it might scale PAL to NTSC or vice versa > >>> if the standard switches mid-stream. Or it only detects the standard when > >>> it starts streaming, I'm not sure. > >>> > >> > >> Not sure about this either, IIUC switching the standard mid-stream won't work. > > > > As far as I know, the detection happens after a sync lost event. > > > > Ah, good to know. > > >>> In any case, this is not normal behavior, for almost all analog video > >>> receivers you need to be able to set the std explicitly. > >>> > >> > >> Indeed. I see that Marco's recent series [0] add supports for the .querystd [1] > >> and .g_std [2] callbacks to the tvp5150 driver, so that way user-space can get > >> back the detected standard. > >> > >> [0]: https://www.spinics.net/lists/linux-media/msg136869.html > >> [1]: https://www.spinics.net/lists/linux-media/msg136872.html > >> [2]: https://www.spinics.net/lists/linux-media/msg136875.html > > > > I tought the std will be set by the v4l2_subdev_video_ops.s_std() > > operation. If the user change the std manually, the autodection is > > disabled. > > > > Yes, what I tried to say is that user-space won't have a way to know which std > to set without a .querystd, or know what std was autodetected withou a .g_std. Now I got you. Yes, thats the only way, as far as I know. > Best regards, Regards, Marco