Message-ID: <1491492354.2392.87.camel@pengutronix.de>
Subject: Re: [PATCH] [media] imx: csi: retain current field order and
 colorimetry setting as default
From: Philipp Zabel <p.zabel@pengutronix.de>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Steve Longerbeam <slongerbeam@gmail.com>, robh+dt@kernel.org,
        mark.rutland@arm.com, shawnguo@kernel.org, kernel@pengutronix.de,
        fabio.estevam@nxp.com, mchehab@kernel.org, hverkuil@xs4all.nl,
        nick@shmanahar.org, markus.heiser@darmarIT.de,
        laurent.pinchart+renesas@ideasonboard.com, bparrot@ti.com,
        geert@linux-m68k.org, arnd@arndb.de, sudipm.mukherjee@gmail.com,
        minghsiu.tsai@mediatek.com, tiffany.lin@mediatek.com,
        jean-christophe.trotin@st.com, horms+renesas@verge.net.au,
        niklas.soderlund+renesas@ragnatech.se, robert.jarzmik@free.fr,
        songjun.wu@microchip.com, andrew-ct.chen@mediatek.com,
        gregkh@linuxfoundation.org, shuah@kernel.org,
        sakari.ailus@linux.intel.com, pavel@ucw.cz, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-media@vger.kernel.org, devel@driverdev.osuosl.org,
        Steve Longerbeam <steve_longerbeam@mentor.com>
Date: Thu, 06 Apr 2017 17:25:54 +0200
In-Reply-To: <20170406151032.GH17774@n2100.armlinux.org.uk>
References: <1490661656-10318-1-git-send-email-steve_longerbeam@mentor.com>
         <1490661656-10318-22-git-send-email-steve_longerbeam@mentor.com>
         <1491486929.2392.29.camel@pengutronix.de>
         <20170406140533.GF17774@n2100.armlinux.org.uk>
         <1491490912.2392.74.camel@pengutronix.de>
         <20170406151032.GH17774@n2100.armlinux.org.uk>
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On Thu, 2017-04-06 at 16:10 +0100, Russell King - ARM Linux wrote:
> On Thu, Apr 06, 2017 at 05:01:52PM +0200, Philipp Zabel wrote:
> > On Thu, 2017-04-06 at 15:05 +0100, Russell King - ARM Linux wrote:
> > > On Thu, Apr 06, 2017 at 03:55:29PM +0200, Philipp Zabel wrote:
> > > > +
> > > > +	/* Retain current field setting as default */
> > > > +	if (sdformat->format.field == V4L2_FIELD_ANY)
> > > > +		sdformat->format.field = fmt->field;
> > > > +
> > > > +	/* Retain current colorspace setting as default */
> > > > +	if (sdformat->format.colorspace == V4L2_COLORSPACE_DEFAULT) {
> > > > +		sdformat->format.colorspace = fmt->colorspace;
> > > > +		if (sdformat->format.xfer_func == V4L2_XFER_FUNC_DEFAULT)
> > > > +			sdformat->format.xfer_func = fmt->xfer_func;
> > > > +		if (sdformat->format.ycbcr_enc == V4L2_YCBCR_ENC_DEFAULT)
> > > > +			sdformat->format.ycbcr_enc = fmt->ycbcr_enc;
> > > > +		if (sdformat->format.quantization == V4L2_QUANTIZATION_DEFAULT)
> > > > +			sdformat->format.quantization = fmt->quantization;
> > > > +	} else {
> > > > +		if (sdformat->format.xfer_func == V4L2_XFER_FUNC_DEFAULT) {
> > > > +			sdformat->format.xfer_func =
> > > > +				V4L2_MAP_XFER_FUNC_DEFAULT(
> > > > +						sdformat->format.colorspace);
> > > > +		}
> > > > +		if (sdformat->format.ycbcr_enc == V4L2_YCBCR_ENC_DEFAULT) {
> > > > +			sdformat->format.ycbcr_enc =
> > > > +				V4L2_MAP_YCBCR_ENC_DEFAULT(
> > > > +						sdformat->format.colorspace);
> > > > +		}
> > > > +		if (sdformat->format.quantization == V4L2_QUANTIZATION_DEFAULT) {
> > > > +			sdformat->format.quantization =
> > > > +				V4L2_MAP_QUANTIZATION_DEFAULT(
> > > > +						cc->cs != IPUV3_COLORSPACE_YUV,
> > > > +						sdformat->format.colorspace,
> > > > +						sdformat->format.ycbcr_enc);
> > > > +		}
> > > > +	}
> > > 
> > > Would it make sense for this to be a helper function?
> > 
> > Quite possible, the next subdev that has to set frame_interval on both
> > pads manually because its upstream source pad doesn't suport
> > frame_interval might want to do the same.
> 
> Hmm.  I'm not sure I agree with this approach.  If a subdev hardware
> does not support any modification of the colourspace or field, then
> it should not be modifyable at the source pad - it should retain the
> propagated settings from the sink pad.

This new code is only relevant for the CSI_SINK_PAD.

> I thought I had already sent a patch doing exactly that.

Yes. Right above the modification there is a call to csi_try_fmt which
will already fix up sdformat->format for the source pads. So for the
CSI_SRC_PAD_DIRECT and CSI_SRC_PAD_IDMAC this should amount to a no-op.

If might be better to move this into a separate function and only call
it if sdformat->pad == CSI_SINK_PAD.

regards
Philipp