From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BF3BC433DF for ; Sun, 28 Jun 2020 20:27:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21DFC206E9 for ; Sun, 28 Jun 2020 20:27:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="QI8lonjy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726080AbgF1U1H (ORCPT ); Sun, 28 Jun 2020 16:27:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726011AbgF1U1H (ORCPT ); Sun, 28 Jun 2020 16:27:07 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF836C03E979 for ; Sun, 28 Jun 2020 13:27:06 -0700 (PDT) Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 0C07F4FB; Sun, 28 Jun 2020 22:27:02 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1593376023; bh=e6nORgmVothb1fYeN60nWx2Gck3W2vO5viZCmQZ4TSU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QI8lonjy0wZjXrK57J92FW7bEfGUCo1YmLk/dVFSx+eotyQrk4GZPH4DjeSs+RqJ1 tZqQS15sApZLdaYVMcoRkK5zOy21tCXBT6rdsT0FbGr1L/ijxBQxTZPEDA3xaEN4u5 QvhqKyp1bB5tz1rJqdk56Aw7SN9qUzJxP18lCigA= Date: Sun, 28 Jun 2020 23:27:00 +0300 From: Laurent Pinchart To: Tomasz Figa Cc: Helen Koike , Dafna Hirschfeld , Linux Media Mailing List , Ezequiel Garcia , Hans Verkuil , kernel@collabora.com, Dafna Hirschfeld , "open list:ARM/Rockchip SoC..." , Sakari Ailus Subject: Re: [RFC v3 2/2] media: staging: rkisp1: allow quantization conversion from userspace for isp source pad Message-ID: <20200628202700.GV6954@pendragon.ideasonboard.com> References: <62611ccd-e4cd-728a-355b-532661b36be0@collabora.com> <20200618184923.GB68039@chromium.org> <20200618192535.GD73379@chromium.org> <67cdd3be-ee2a-3b88-5d17-d9d1d17b2603@collabora.com> <20200628131537.GT6954@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Tomasz, On Sun, Jun 28, 2020 at 04:59:34PM +0200, Tomasz Figa wrote: > On Sun, Jun 28, 2020 at 3:15 PM Laurent Pinchart wrote: > > On Sun, Jun 28, 2020 at 03:10:41PM +0200, Tomasz Figa wrote: > >> On Fri, Jun 26, 2020 at 2:15 AM Helen Koike wrote: > >>> On 6/18/20 4:25 PM, Tomasz Figa wrote: > >>>> On Thu, Jun 18, 2020 at 08:54:34PM +0200, Dafna Hirschfeld wrote: > >>>>> On 18.06.20 20:49, Tomasz Figa wrote: > >>>>>> On Thu, Jun 18, 2020 at 08:26:33PM +0200, Dafna Hirschfeld wrote: > >>>>>>> On 18.06.20 19:27, Tomasz Figa wrote: > >>>>>>>> On Wed, Jun 10, 2020 at 2:08 PM Tomasz Figa wrote: > >>>>>>>>> On Thu, Jun 4, 2020 at 9:11 PM Dafna Hirschfeld wrote: > >>>>>>>>>> On 04.06.20 19:54, Tomasz Figa wrote: > >>>>>>>>>>> On Thu, Apr 16, 2020 at 04:56:05PM +0200, Dafna Hirschfeld wrote: > >>>>>>>>>>>> The isp entity has a hardware support to force full range quantization > >>>>>>>>>>>> for YUV formats. Use the new API to indicate userspace that > >>>>>>>>>>>> quantization conversion is supported by adding the flag > >>>>>>>>>>>> V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION during media code enumeration. > >>>>>>>>>>>> Then uppon s_fmt on the video source pad, we assign the > >>>>>>>>>>>> quantization from userspace for YUV formats. > >>>>>>>>>>>> Also in the capture and resizer entities we retrieve the colorspace > >>>>>>>>>>>> from the isp entity. > >>>>>>>>>>>> > >>>>>>>>>>>> Signed-off-by: Dafna Hirschfeld > >>>>>>>>>>>> --- > >>>>>>>>>>>> drivers/staging/media/rkisp1/rkisp1-capture.c | 28 ++++++------- > >>>>>>>>>>>> drivers/staging/media/rkisp1/rkisp1-common.h | 2 + > >>>>>>>>>>>> drivers/staging/media/rkisp1/rkisp1-isp.c | 39 +++++++++++++++++-- > >>>>>>>>>>>> drivers/staging/media/rkisp1/rkisp1-resizer.c | 13 +++++++ > >>>>>>>>>>>> 4 files changed, 65 insertions(+), 17 deletions(-) > >>>>>>>>>>>> > >>>>>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-capture.c b/drivers/staging/media/rkisp1/rkisp1-capture.c > >>>>>>>>>>>> index fbf62399fe3d..aca0f93bc772 100644 > >>>>>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-capture.c > >>>>>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-capture.c > >>>>>>>>>>>> @@ -1066,14 +1066,13 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap, > >>>>>>>>>>>> const struct v4l2_format_info **fmt_info) > >>>>>>>>>>>> { > >>>>>>>>>>>> const struct rkisp1_capture_config *config = cap->config; > >>>>>>>>>>>> - struct rkisp1_capture *other_cap = > >>>>>>>>>>>> - &cap->rkisp1->capture_devs[cap->id ^ 1]; > >>>>>>>>>>>> const struct rkisp1_capture_fmt_cfg *fmt; > >>>>>>>>>>>> const struct v4l2_format_info *info; > >>>>>>>>>>>> const unsigned int max_widths[] = { RKISP1_RSZ_MP_SRC_MAX_WIDTH, > >>>>>>>>>>>> RKISP1_RSZ_SP_SRC_MAX_WIDTH }; > >>>>>>>>>>>> const unsigned int max_heights[] = { RKISP1_RSZ_MP_SRC_MAX_HEIGHT, > >>>>>>>>>>>> RKISP1_RSZ_SP_SRC_MAX_HEIGHT}; > >>>>>>>>>>>> + struct v4l2_subdev_format isp_sd_fmt; > >>>>>>>>>>>> > >>>>>>>>>>>> fmt = rkisp1_find_fmt_cfg(cap, pixm->pixelformat); > >>>>>>>>>>>> if (!fmt) { > >>>>>>>>>>>> @@ -1081,24 +1080,27 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap, > >>>>>>>>>>>> pixm->pixelformat = fmt->fourcc; > >>>>>>>>>>>> } > >>>>>>>>>>>> > >>>>>>>>>>>> + rkisp1_get_isp_src_fmt(cap->rkisp1, &isp_sd_fmt); > >>>>>>>>>>>> + pixm->field = isp_sd_fmt.format.field; > >>>>>>>>>>>> + pixm->colorspace = isp_sd_fmt.format.colorspace; > >>>>>>>>>>>> + pixm->ycbcr_enc = isp_sd_fmt.format.ycbcr_enc; > >>>>>>>>>>>> + pixm->xfer_func = isp_sd_fmt.format.xfer_func; > >>>>>>>>>>>> + > >>>>>>>>>>>> + /* > >>>>>>>>>>>> + * isp has a feature to set full range quantization for yuv formats. > >>>>>>>>>>> > >>>>>>>>>>> How about "select between limited and full range for YUV formats"? > >>>>>>>>>>> > >>>>>>>>>>>> + * so we need to get the format from the isp. > >>>>>>>>>>>> + */ > >>>>>>>>>>>> + pixm->quantization = isp_sd_fmt.format.quantization; > >>>>>>>>>>>> + if (!v4l2_is_format_yuv(cap->pix.info)) > >>>>>>>>>>>> + pixm->quantization = V4L2_QUANTIZATION_FULL_RANGE; > >>>>>>>>>>>> + > >>>>>>>>>>>> pixm->width = clamp_t(u32, pixm->width, > >>>>>>>>>>>> RKISP1_RSZ_SRC_MIN_WIDTH, max_widths[cap->id]); > >>>>>>>>>>>> pixm->height = clamp_t(u32, pixm->height, > >>>>>>>>>>>> RKISP1_RSZ_SRC_MIN_HEIGHT, max_heights[cap->id]); > >>>>>>>>>>>> > >>>>>>>>>>>> - pixm->field = V4L2_FIELD_NONE; > >>>>>>>>>>>> - pixm->colorspace = V4L2_COLORSPACE_DEFAULT; > >>>>>>>>>>>> - pixm->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT; > >>>>>>>>>>>> - > >>>>>>>>>>>> info = rkisp1_fill_pixfmt(pixm, cap->id); > >>>>>>>>>>>> > >>>>>>>>>>>> - /* can not change quantization when stream-on */ > >>>>>>>>>>>> - if (other_cap->is_streaming) > >>>>>>>>>>>> - pixm->quantization = other_cap->pix.fmt.quantization; > >>>>>>>>>>>> - /* output full range by default, take effect in params */ > >>>>>>>>>>>> - else if (!pixm->quantization || > >>>>>>>>>>>> - pixm->quantization > V4L2_QUANTIZATION_LIM_RANGE) > >>>>>>>>>>>> - pixm->quantization = V4L2_QUANTIZATION_FULL_RANGE; > >>>>>>>>>>>> > >>>>>>>>>>>> if (fmt_cfg) > >>>>>>>>>>>> *fmt_cfg = fmt; > >>>>>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-common.h b/drivers/staging/media/rkisp1/rkisp1-common.h > >>>>>>>>>>>> index 2d7b7e078636..7a5576fa14c9 100644 > >>>>>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-common.h > >>>>>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-common.h > >>>>>>>>>>>> @@ -300,6 +300,8 @@ int rkisp1_isp_register(struct rkisp1_device *rkisp1, > >>>>>>>>>>>> struct v4l2_device *v4l2_dev); > >>>>>>>>>>>> void rkisp1_isp_unregister(struct rkisp1_device *rkisp1); > >>>>>>>>>>>> > >>>>>>>>>>>> +int rkisp1_get_isp_src_fmt(struct rkisp1_device *rkisp1, > >>>>>>>>>>>> + struct v4l2_subdev_format *sd_fmt); > >>>>>>>>>>>> const struct rkisp1_isp_mbus_info *rkisp1_isp_mbus_info_get(u32 mbus_code); > >>>>>>>>>>>> > >>>>>>>>>>>> irqreturn_t rkisp1_isp_isr(struct rkisp1_device *rkisp1); > >>>>>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-isp.c b/drivers/staging/media/rkisp1/rkisp1-isp.c > >>>>>>>>>>>> index dee8e96f3900..6fdf5ed0b6b1 100644 > >>>>>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-isp.c > >>>>>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-isp.c > >>>>>>>>>>>> @@ -613,6 +613,10 @@ static int rkisp1_isp_enum_mbus_code(struct v4l2_subdev *sd, > >>>>>>>>>>>> > >>>>>>>>>>>> if (code->index == pos - 1) { > >>>>>>>>>>>> code->code = fmt->mbus_code; > >>>>>>>>>>>> + if (fmt->pixel_enc == V4L2_PIXEL_ENC_YUV && > >>>>>>>>>>>> + dir == RKISP1_DIR_SRC) > >>>>>>>>>>>> + code->flags = > >>>>>>>>>>>> + V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION; > >>>>>>>>>>>> return 0; > >>>>>>>>>>>> } > >>>>>>>>>>>> } > >>>>>>>>>>>> @@ -639,12 +643,21 @@ static int rkisp1_isp_init_config(struct v4l2_subdev *sd, > >>>>>>>>>>>> sink_crop->height = RKISP1_DEFAULT_HEIGHT; > >>>>>>>>>>>> sink_crop->left = 0; > >>>>>>>>>>>> sink_crop->top = 0; > >>>>>>>>>>>> + sink_fmt->colorspace = V4L2_COLORSPACE_SRGB; > >>>>>>>>>>>> + sink_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(sink_fmt->colorspace); > >>>>>>>>>>>> + sink_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(sink_fmt->colorspace); > >>>>>>>>>>>> + sink_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE; > >>>>>>>>>>>> + > >>>>>>>>>>>> > >>>>>>>>>>>> src_fmt = v4l2_subdev_get_try_format(sd, cfg, > >>>>>>>>>>>> RKISP1_ISP_PAD_SOURCE_VIDEO); > >>>>>>>>>>>> *src_fmt = *sink_fmt; > >>>>>>>>>>>> src_fmt->code = RKISP1_DEF_SRC_PAD_FMT; > >>>>>>>>>>>> - src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE; > >>>>>>>>>>>> + src_fmt->colorspace = V4L2_COLORSPACE_SRGB; > >>>>>>>>>>>> + src_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(src_fmt->colorspace); > >>>>>>>>>>>> + src_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(src_fmt->colorspace); > >>>>>>>>>>>> + src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE; > >>>>>>>>>>>> + > >>>>>>>>>>>> > >>>>>>>>>>>> src_crop = v4l2_subdev_get_try_crop(sd, cfg, > >>>>>>>>>>>> RKISP1_ISP_PAD_SOURCE_VIDEO); > >>>>>>>>>>>> @@ -687,10 +700,17 @@ static void rkisp1_isp_set_src_fmt(struct rkisp1_isp *isp, > >>>>>>>>>>>> isp->src_fmt = mbus_info; > >>>>>>>>>>>> src_fmt->width = src_crop->width; > >>>>>>>>>>>> src_fmt->height = src_crop->height; > >>>>>>>>>>>> - src_fmt->quantization = format->quantization; > >>>>>>>>>>>> - /* full range by default */ > >>>>>>>>>>>> - if (!src_fmt->quantization) > >>>>>>>>>>>> + > >>>>>>>>>>>> + src_fmt->colorspace = V4L2_COLORSPACE_SRGB; > >>>>>>>>>>>> + src_fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(src_fmt->colorspace); > >>>>>>>>>>>> + src_fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(src_fmt->colorspace); > >>>>>>>>>>>> + > >>>>>>>>>>>> + if (mbus_info->pixel_enc == V4L2_PIXEL_ENC_BAYER) > >>>>>>>>>>>> src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE; > >>>>>>>>>>>> + else if (format->quantization == V4L2_QUANTIZATION_DEFAULT) > >>>>>>>>>>>> + src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE; > >>>>>>>>>>>> + else > >>>>>>>>>>>> + src_fmt->quantization = format->quantization; > >>>>>>>>>>>> > >>>>>>>>>>>> *format = *src_fmt; > >>>>>>>>>>>> } > >>>>>>>>>>>> @@ -1068,6 +1088,17 @@ int rkisp1_isp_register(struct rkisp1_device *rkisp1, > >>>>>>>>>>>> return ret; > >>>>>>>>>>>> } > >>>>>>>>>>>> > >>>>>>>>>>>> +int rkisp1_get_isp_src_fmt(struct rkisp1_device *rkisp1, > >>>>>>>>>>>> + struct v4l2_subdev_format *sd_fmt) > >>>>>>>>>>>> +{ > >>>>>>>>>>>> + struct rkisp1_isp *isp = &rkisp1->isp; > >>>>>>>>>>>> + > >>>>>>>>>>>> + sd_fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE; > >>>>>>>>>>>> + sd_fmt->pad = RKISP1_ISP_PAD_SOURCE_VIDEO; > >>>>>>>>>>>> + > >>>>>>>>>>>> + return v4l2_subdev_call(&isp->sd, pad, get_fmt, NULL, sd_fmt); > >>>>>>>>>>> > >>>>>>>>>>> Do we need to get through the external API to access data that is > >>>>>>>>>>> driver-internal anyway? > >>>>>>>>>>> > >>>>>>>>>>>> +} > >>>>>>>>>>>> + > >>>>>>>>>>>> void rkisp1_isp_unregister(struct rkisp1_device *rkisp1) > >>>>>>>>>>>> { > >>>>>>>>>>>> struct v4l2_subdev *sd = &rkisp1->isp.sd; > >>>>>>>>>>>> diff --git a/drivers/staging/media/rkisp1/rkisp1-resizer.c b/drivers/staging/media/rkisp1/rkisp1-resizer.c > >>>>>>>>>>>> index 7b6b7ddd4169..8705b133de68 100644 > >>>>>>>>>>>> --- a/drivers/staging/media/rkisp1/rkisp1-resizer.c > >>>>>>>>>>>> +++ b/drivers/staging/media/rkisp1/rkisp1-resizer.c > >>>>>>>>>>>> @@ -525,6 +525,7 @@ static void rkisp1_rsz_set_sink_fmt(struct rkisp1_resizer *rsz, > >>>>>>>>>>>> const struct rkisp1_isp_mbus_info *mbus_info; > >>>>>>>>>>>> struct v4l2_mbus_framefmt *sink_fmt, *src_fmt; > >>>>>>>>>>>> struct v4l2_rect *sink_crop; > >>>>>>>>>>>> + struct v4l2_subdev_format isp_sd_fmt; > >>>>>>>>>>>> > >>>>>>>>>>>> sink_fmt = rkisp1_rsz_get_pad_fmt(rsz, cfg, RKISP1_RSZ_PAD_SINK, which); > >>>>>>>>>>>> src_fmt = rkisp1_rsz_get_pad_fmt(rsz, cfg, RKISP1_RSZ_PAD_SRC, which); > >>>>>>>>>>>> @@ -539,8 +540,20 @@ static void rkisp1_rsz_set_sink_fmt(struct rkisp1_resizer *rsz, > >>>>>>>>>>>> if (which == V4L2_SUBDEV_FORMAT_ACTIVE) > >>>>>>>>>>>> rsz->pixel_enc = mbus_info->pixel_enc; > >>>>>>>>>>>> > >>>>>>>>>>>> + rkisp1_get_isp_src_fmt(rsz->rkisp1, &isp_sd_fmt); > >>>>>>>>>>>> + > >>>>>>>>>>> > >>>>>>>>>>> Is this necessary? My understanding was that in the subdev model, it was > >>>>>>>>>>> the userspace responsibility to propagate any configuration changes through > >>>>>>>>>>> the graph. > >>>>>>>>>>> > >>>>>>>>>>> Also, doing this only here wouldn't fully maintain the > >>>>>>>>>>> consistency of the state. For example, if one sets the ISP subdev format > >>>>>>>>>>> first, then the resizer subdev and then the ISP subdev again, wouldn't the > >>>>>>>>>>> resizer subdev end up with a wrong format? > >>>>>>>>>> > >>>>>>>>>> yes, this is indeed a bug, I am preparing v4 now. > >>>>>>>>>> What I thought to do is adding quantization conversion > >>>>>>>>>> support also on ther resizer and capture entities. > >>>>>>>>>> Then in the 'link_validation' callbacks, there > >>>>>>>>>> is a validation that the quantization fields matches. > >>>>>>>>> > >>>>>>>>> My understanding is that, if we have the following topology > >>>>>>>>> > >>>>>>>>> [ ISP ] -> [ Resizer ] -> [ Video node ] > >>>>>>>>> > >>>>>>>>> then the ISP source pad would have the csc capability, while resizer > >>>>>>>>> and video node would just accept whatever is configured on their sink > >>>>>>>>> pads (no need for csc capability for that) and propagate that to their > >>>>>>>>> outputs, i.e. resizer source pad and video node CAPTURE format. > >>>>>>>>> > >>>>>>>>> Is this what you were going to implement? > >>>>>>> Hi, I sent a v4 where the CSC capability is set on the reiszer and capture as well. > >>>>>>> I can send a v5 implementing it the way you suggest. Currently the doc says that the colorspace fields > >>>>>>> must be set by the driver for capture streams. This implies that userspace can set it > >>>>>>> only if the CSC is supported. > >>>>>> > >>>>>> Why would the userspace have to set it for the capture stream on the > >>>>>> resizer and video nodes? Couldn't the userspace set it to DEFAULT and > >>>>>> then the driver override to whatever it received on the corresponding > >>>>>> sink? > >>> > >>> According to the documentation [1]: > >>> > >>> "the default quantization encoding as defined by the colorspace" > >>> > >>> Then, for instance, the default for V4L2_COLORSPACE_SRGB is limited range [2]. > >>> > >>> Unless we change the definition of DEFAULT to let it accept whatever it receives on the corresponding sink. > >>> > >>> Then the way I understand is: > >>> > >>> [sensor]->[isp]->[resizer]->[capture] > >>> > >>> Userspace should set quantization on: > >>> * sensor source pad > >>> * isp sink pad > >>> * resizer sink pad > >>> * capture node > >>> > >>> The remaining source pads would get values propagated from their sink pads. > >>> > >>> [1] https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/colorspaces-defs.html#c.v4l2_quantization > >>> [2] https://linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/v4l/colorspaces-details.html#col-srgb > >> > >> After discussing this offline, we concluded that: > >> - only the source pad of the ISP entity should expose the CSC capability, > >> - the CAPTURE video node should expose only the formats/color spaces > >> compatible with the current setting of the resizer source, > >> - consistency between the resizer source format and CAPTURE format > >> should be implicitly maintained by the driver. > > > > Do you mean it should be validated at streamon time ? > > Nope. Any V4L2 state must be kept valid all the time, as mandated by > the general V4L2 principles. Wrong configuration of the video node > must not be a reason for STREAMON failing. That's a wrong interpretation of V4L2. On a video-node-centric device (a device that doesn't use the subdev userspace API for configuration) this is correct. In a MC-centric device, the video node and its connected subdev are configured separately. > > In MC-based > > drivers, entities are isolated from each other from a configuration > > point of view, and the validity of the configuration across the whole > > pipeline is checked at streamon time. I don't think CSC parameters > > should be treated differently than formats in this regard. > > Indeed, the ISP entity and the resizer entity are isolated from each > other and they need to be validated separately. However, the resizer > entity is not isolated from the video node, as there is no > configuration exposed for the video node in the MC API. If MC exposed > an explicit format control for the video interface sink pad, then the > resizer would have to be validated separately indeed, but still that > video interface sink pad would be tied to the rest of the > configuration of the video node (e.g. the CAPTURE format). > > >> Below is the rationale for that: > >> - In the MC model, the video node represents the DMA alone (and thus > >> the reason to have the resizer entities at all) and since the > >> colorspace is not a property of the DMA, it doesn't belong there. > >> - Even if we put that aside, both MP and SP can only output the same > >> colorspace, which would create a dependency between the configuration > >> of the two video nodes, which is not something well defined by V4L2. > >> - A video interface in the MC API doesn't expose control over its > >> input format, which means that the relation between the other side of > >> the link (resizer source) and the video node is implicit and needs to > >> be handled internally in the driver. > >> - V4L2, as opposed to MC, requires that the current state is always > >> consistent and valid. In this case it means that an ioctl on the video > >> node must not be able to alter the state in a way that would make it > >> inconsistent with the state of the matching resizer source. -- Regards, Laurent Pinchart