Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751834AbdCMIRi (ORCPT ); Mon, 13 Mar 2017 04:17:38 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:54714 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbdCMIRd (ORCPT ); Mon, 13 Mar 2017 04:17:33 -0400 Date: Mon, 13 Mar 2017 08:16:25 +0000 From: Russell King - ARM Linux To: Steve Longerbeam Cc: 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, p.zabel@pengutronix.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 Subject: Re: [PATCH v5 00/39] i.MX Media Driver Message-ID: <20170313081625.GX21222@n2100.armlinux.org.uk> References: <1489121599-23206-1-git-send-email-steve_longerbeam@mentor.com> <20170310201356.GA21222@n2100.armlinux.org.uk> <47542ef8-3e91-b4cd-cc65-95000105f172@gmail.com> <20170312195741.GS21222@n2100.armlinux.org.uk> <20170312202240.GT21222@n2100.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3319 Lines: 77 On Sun, Mar 12, 2017 at 09:26:41PM -0700, Steve Longerbeam wrote: > On 03/12/2017 01:22 PM, Russell King - ARM Linux wrote: > >What I had was this patch for your v3. I never got to testing your > >v4 because of the LP-11 problem. > > > >In v5, you've changed to propagate the ipu_cpmem_set_image() error > >code to avoid the resulting corruption, but that leaves the other bits > >of this patch unaddressed, along my "media: imx: smfc: add support > >for bayer formats" patch. > > > >Your driver basically has no support for bayer formats. > > You added the patches to this driver that adds the bayer support, > I don't think there is anything more required of the driver at this > point to support bayer, the remaining work needs to happen in the IPUv3 > driver. There is more work, because the way you've merged my changes to imx_smfc_setup_channel() into csi_idmac_setup_channel() is wrong with respect to the burst size. You always set it to 8 or 16 depending on the width: burst_size = (image.pix.width & 0xf) ? 8 : 16; ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size); and then you have my switch() statement which assigns burst_size. My _tested_ code removed the above, added the switch, which had a default case which reflected the above setting: default: burst_size = (outfmt->width & 0xf) ? 8 : 16; and then went on to set the burst size _after_ the switch statement: ipu_cpmem_set_burstsize(priv->smfc_ch, burst_size); The effect is unchanged for non-bayer formats. For bayer formats, the burst size is determined by the bayer data size. So, even if it's appropriate to fix ipu_cpmem_set_image(), fixing the above is still required. I'm not convinced that fixing ipu_cpmem_set_image() is even the best solution - it's not as trivial as it looks on the surface: ipu_cpmem_set_resolution(ch, image->rect.width, image->rect.height); ipu_cpmem_set_stride(ch, pix->bytesperline); this is fine, it doesn't depend on the format. However, the next line: ipu_cpmem_set_fmt(ch, v4l2_pix_fmt_to_drm_fourcc(pix->pixelformat)); does - v4l2_pix_fmt_to_drm_fourcc() is a locally defined function (it isn't v4l2 code) that converts a v4l2 pixel format to a DRM fourcc. DRM knows nothing about bayer formats, there aren't fourcc codes in DRM for it. The result is that v4l2_pix_fmt_to_drm_fourcc() returns -EINVAL cast to a u32, which gets passed unchecked into ipu_cpmem_set_fmt(). ipu_cpmem_set_fmt() won't recognise that, and also returns -EINVAL - and it's a bug that this is not checked and propagated. If it is checked and propagated, then we need this to support bayer formats, and I don't see DRM people wanting bayer format fourcc codes added without there being a real DRM driver wanting to use them. Then there's the business of calculating the top-left offset of the image, which for bayer always needs to be an even number of pixels - as this function takes the top-left offset, it ought to respect it, but if it doesn't meet this criteria, what should it do? csi_idmac_setup_channel() always sets them to zero, but that's not really something that ipu_cpmem_set_image() should assume. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.