From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:29497 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751495Ab1DZLxy (ORCPT ); Tue, 26 Apr 2011 07:53:54 -0400 Message-ID: <4DB6B28D.5090607@redhat.com> Date: Tue, 26 Apr 2011 13:54:53 +0200 From: Hans de Goede MIME-Version: 1.0 To: Ondrej Zary CC: Hans Verkuil , Joerg Heckenbach , Dwaine Garden , linux-media@vger.kernel.org, Kernel development list Subject: Re: [PATCH] usbvision: remove (broken) image format conversion References: <201104252323.20420.linux@rainbow-software.org> <201104260832.11150.hverkuil@xs4all.nl> <201104261030.21681.linux@rainbow-software.org> In-Reply-To: <201104261030.21681.linux@rainbow-software.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-ID: Sender: Hi, On 04/26/2011 10:30 AM, Ondrej Zary wrote: > On Tuesday 26 April 2011, you wrote: >> On Monday, April 25, 2011 23:23:17 Ondrej Zary wrote: >>> The YVU420 and YUV422P formats are broken and cause kernel panic on use. >>> (YVU420 does not work and sometimes causes "unable to handle paging >>> request" panic, YUV422P always causes "NULL pointer dereference"). >>> >>> As V4L2 spec says that drivers shouldn't do any in-kernel image format >>> conversion, remove it completely (except YUYV). >> >> What really should happen is that the conversion is moved to libv4lconvert. >> I've never had the time to tackle that, but it would improve this driver a >> lot. > > Depending on isoc_mode module parameter, the device uses different image > formats: YUV 4:2:2 interleaved, YUV 4:2:0 planar or compressed format. > > Maybe the parameter should go away and these three formats exposed to > userspace? That sounds right, > Hopefully the non-compressed formats could be used directly > without any conversion. But the compressed format (with new V4L2_PIX_FMT_ > assigned?) should be preferred (as it provides much higher frame rates). The > code moved into libv4lconvert would decompress the format and convert into > something standard (YUV420?). Correct. > >> Would you perhaps be interested in doing that work? > > I can try it. But the hardware isn't mine so my time is limited. > If you could give it a shot that would be great. I've some hardware to test this with (although I've never actually tested that hardware), so I can hopefully pick things up if you cannot finish things before you need to return the hardware. Thanks & Regards, Hans