From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-68.nebula.fi ([83.145.220.68]:58828 "EHLO smtp-68.nebula.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755038Ab2AJJw2 (ORCPT ); Tue, 10 Jan 2012 04:52:28 -0500 Message-ID: <4F0C0A5A.9060708@iki.fi> Date: Tue, 10 Jan 2012 11:52:26 +0200 From: Sakari Ailus MIME-Version: 1.0 To: Laurent Pinchart CC: linux-media@vger.kernel.org, tuukkat76@gmail.com, dacohen@gmail.com, g.liakhovetski@gmx.de, hverkuil@xs4all.nl, snjw23@gmail.com Subject: Re: [ANN] Notes on IRC meeting on new sensor control interface, 2012-01-09 14:00 GMT+2 References: <20120104085633.GM3677@valkosipuli.localdomain> <201201100113.07211.laurent.pinchart@ideasonboard.com> <4F0C0822.6020604@iki.fi> <201201101050.52887.laurent.pinchart@ideasonboard.com> In-Reply-To: <201201101050.52887.laurent.pinchart@ideasonboard.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Laurent Pinchart wrote: > Hi Sakari, > > On Tuesday 10 January 2012 10:42:58 Sakari Ailus wrote: >> Laurent Pinchart wrote: >>> On Tuesday 10 January 2012 00:26:46 Sakari Ailus wrote: >>>> Laurent Pinchart wrote: >>>>> On Monday 09 January 2012 23:32:06 Sakari Ailus wrote: >>>>>> Laurent Pinchart wrote: >>>>>>> On Monday 09 January 2012 18:38:25 Sakari Ailus wrote: >>>> ... >>>> >>>>>>>> A fourth section may be required as well: at this level the frame >>>>>>>> rate (or frame time) range makes more sense than the low-level >>>>>>>> blanking values. The blanking values can be calculated from the >>>>>>>> frame time and a flag which tells whether either horizontal or >>>>>>>> vertical blanking should be preferred. >>>>>>> >>>>>>> How does one typically select between horizontal and vertical >>>>>>> blanking ? Do mixed modes make sense ? >>>>>> >>>>>> There are minimums and maximums for both. You can increase the frame >>>>>> time by increasing value for either or both of them --- to achieve >>>>>> very long frame times you may have to use both, but that's not very >>>>>> common in practice. I think we should have a flag to tell which one >>>>>> should be increased first --- the effect would be to have the minimum >>>>>> possible value on the other. >>>>> >>>>> But how do you decide in practice which one to increase when you're an >>>>> application (or middleware) developer ? >>>> >>>> I think it's the responsibility of this library to do that, unless the >>>> user wants really, really precise control in which case they have to >>>> deal with the blanking values directly. In general it should be the >>>> library. >>> >>> And how does the library decide ? :-) >> >> frame_time = pixel_rate / ((width + hblank) * (height + vblank)) >> >> The user gives you frame time and the configuration contains the >> information which one to prefer. Let's say the user prefers hblank (from >> the above): > > That was my question, how does the user decide whether hblank or vblank is > preferred ? I think that should be defined in the configuration itself. It's very unlikely there's any need to change this dynamically. -- Sakari Ailus sakari.ailus@iki.fi