From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753932AbdFSKDe (ORCPT ); Mon, 19 Jun 2017 06:03:34 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:2489 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753783AbdFSKDc (ORCPT ); Mon, 19 Jun 2017 06:03:32 -0400 Message-ID: <1497866607.25194.14.camel@mtksdaap41> Subject: Re: [PATCH v2] [media] mtk-mdp: Fix g_/s_selection capture/compose logic From: Minghsiu Tsai To: Hans Verkuil CC: Hans Verkuil , , "Rob Herring" , Mauro Carvalho Chehab , Matthias Brugger , Daniel Kurtz , Pawel Osciak , Houlong Wei , , "Eddie Huang" , Yingjoe Chen , Wu-Cheng Li , , , , , Date: Mon, 19 Jun 2017 18:03:27 +0800 In-Reply-To: References: <1494556970-12278-1-git-send-email-minghsiu.tsai@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Hans, On Fri, 2017-06-16 at 12:42 +0200, Hans Verkuil wrote: > On 05/12/17 04:42, Minghsiu Tsai wrote: > > From: Daniel Kurtz > > > > Experiments show that the: > > (1) mtk-mdp uses the _MPLANE form of CAPTURE/OUTPUT > > Please drop this, since this no longer applies to this patch. > I will remove it next version > > (2) CAPTURE types use CROP targets, and OUTPUT types use COMPOSE targets > > Are you really certain about this? > > For m2m devices the output (i.e. memory to hardware) typically crops from memory > and the capture side (hardware to memory) composes into memory. > > I.e.: for the output side you crop the part of the memory buffer that you want > to process and on the capture side you compose the result into a memory buffer: > i.e. the memory buffer might be 1920x1080, but you compose the decoder output > into a rectangle of 640x480 at offset 128x128 within that buffer (just an example). > > CAPTURE using crop would be if, before the data is DMAed, the hardware decoder > output is cropped. E.g. if the stream fed to the decoder is 1920x1080, but you > want to only DMA a subselection of that, then that would be cropping, and it > would go to a memory buffer of the size of the crop selection. > > OUTPUT using compose is highly unlikely: that means that the frame you give > is composed in a larger internal buffer with generated border data around it. > Very rare and really only something that a compositor of some sort would do. > That's strange. In v4l2-ioctl.c, v4l_g_crop() OUTPUT is using COMPOSE CAPTURE is using CROP static int v4l_g_crop(const struct v4l2_ioctl_ops *ops, struct file *file, void *fh, void *arg) ... /* crop means compose for output devices */ if (V4L2_TYPE_IS_OUTPUT(p->type)) s.target = V4L2_SEL_TGT_COMPOSE_ACTIVE; else s.target = V4L2_SEL_TGT_CROP_ACTIVE; ret = ops->vidioc_g_selection(file, fh, &s); > What exactly does the hardware do? Both for the encoder and for the decoder > case. Perhaps if I knew exactly what that is, then I can advise. > NV12M/YUV420M/MT21 -> MDP -> NV12M/YUV420M The usage would be like this: For decoder: decoder -> MT21 -> MDP -> NV12M/YUV420M For encoder: NV12M/YUV420M -> MDP -> NV12M/YUV420M -> encoder > Regards, > > Hans >