From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:38274 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753430Ab2CSXVi (ORCPT ); Mon, 19 Mar 2012 19:21:38 -0400 From: Laurent Pinchart To: Michael Jones Cc: linux-media ML Subject: Re: reading config parameters of omap3-isp subdevs Date: Tue, 20 Mar 2012 00:22:04 +0100 Message-ID: <6085689.3CUf0tMs8E@avalon> In-Reply-To: <4F6348D7.9070409@matrix-vision.de> References: <4F6348D7.9070409@matrix-vision.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Michael, On Friday 16 March 2012 15:06:15 Michael Jones wrote: > Hi all, > > I am playing around with some parameters in the previewer on the ISP. With > ioctl VIDIOC_OMAP3ISP_PRV_CFG I am able to write the various parameters but > what I'm missing is a way to read them. For example, I have no way to adjust > only coef2 in 'struct omap3isp_prev_wbal' while leaving the others > unchanged. If I could first read the whole omap3isp_prev_wbal structure, > then I could change just the things I want to change. This seems like it > would be common functionality for such ioctls. I didn't find any previous > discussion related to this. > > I could imagine either adding a r/w flag to 'struct > omap3isp_prev_update_config' or adding a new ioctl entirely. I think I > would prefer the r/w flag. Feedback? > > I noticed that other ISP subdevs have similar ioctls. Perhaps a similar > thing would be useful there, but right now I'm only looking at the > previewer. Adding a R/W bit to the flag argument should indeed work. However, I'm wondering what your use case for reading parameters back is. The preview engine parameter structures seem pretty-much self-contained to me, I'm not sure it would make sense to only modify one of the parameters. -- Regards, Laurent Pinchart