Re: [PATCH v5] media: imx: add mem2mem device

From: Philipp Zabel <p.zabel@pengutronix.de>
To: Nicolas Dufresne <nicolas@ndufresne.ca>, linux-media@vger.kernel.org
Cc: Hans Verkuil <hans.verkuil@cisco.com>,
	Steve Longerbeam <slongerbeam@gmail.com>,
	kernel@pengutronix.de
Subject: Re: [PATCH v5] media: imx: add mem2mem device
Date: Tue, 08 Jan 2019 16:30:28 +0100	[thread overview]
Message-ID: <1546961428.5406.4.camel@pengutronix.de> (raw)
In-Reply-To: <4acdd5bd4af28f33ae60d4ac244292e71dd9780d.camel@ndufresne.ca>

Hi Nicolas,

On Mon, 2019-01-07 at 17:36 -0500, Nicolas Dufresne wrote:
> Le lundi 03 décembre 2018 à 12:48 +0100, Philipp Zabel a écrit :
> > Add a single imx-media mem2mem video device that uses the IPU IC PP
> > (image converter post processing) task for scaling and colorspace
> > conversion.
> > On i.MX6Q/DL SoCs with two IPUs currently only the first IPU is used.
> > 
> > The hardware only supports writing to destination buffers up to
> > 1024x1024 pixels in a single pass, arbitrary sizes can be achieved
> > by rendering multiple tiles per frame.
> 
> While testing this driver, I found that the color conversion from YUYV
> to BGR32 is broken.

Thank you for testing, do you mean V4L2_PIX_FMT_RGB32?

V4L2_PIX_FMT_BGR32 is still contained in the ipu_rgb_formats array in
imx-media-utils, but happens to be never returned by enum_fmt since that
already stops at the bayer formats.

>  Our test showed that the output of the m2m driver
> is in fact RGBX/8888, a format that does not yet exist in V4L2
> interface but that is supported by the imx-drm driver. This was tested
> with GStreamer (master of gst-plugins-good), though some changes to
> gst-plugins-bad is needed to add the missing format to kmssink. Let me
> know if you need this to produce or not.
> 
> # To demonstrate (with patched gst-plugins-bad https://paste.fedoraproject.org/paste/rs-CbEq7coL4XSKrnWpEDw)
> gst-launch-1.0 videotestsrc ! video/x-raw,format=YUY2 ! v4l2convert ! video/x-raw,format=xRGB ! kmssink

Is this with an old kernel? Since c525350f6ed0 ("media: imx: use well
defined 32-bit RGB pixel format") that command line should make this
select V4L2_PIX_FMT_XRGB32 ("BX24").

> # Software fix for the color format produced
> gst-launch-1.0 videotestsrc ! video/x-raw,format=YUY2 ! v4l2convert ! video/x-raw,format=xRGB ! capssetter replace=0 caps="video/x-raw,format=RGBx" ! kmssink -v
> 
> Also, BGR32 is deprecated and should not be used, this is mapped by 
> imx_media_enum_format() which I believe is already upstream. If that
> is, this bug is just inherited from that helper.

regards
Philipp