From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guido =?iso-8859-1?Q?G=FCnther?= Subject: Re: [EXT] Re: [PATCH 00/10] Improvements and fixes for mxsfb DRM driver Date: Tue, 16 Jul 2019 16:54:50 +0200 Message-ID: <20190716145450.GA609@bogon.m.sigxcpu.org> References: <1561555938-21595-1-git-send-email-robert.chiras@nxp.com> <20190711150403.GB23195@bogon.m.sigxcpu.org> <1562919331.3209.11.camel@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <1562919331.3209.11.camel@nxp.com> Sender: linux-kernel-owner@vger.kernel.org To: Robert Chiras Cc: "marex@denx.de" , "devicetree@vger.kernel.org" , "kernel@pengutronix.de" , "airlied@linux.ie" , "shawnguo@kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "stefan@agner.ch" , "robh+dt@kernel.org" , dl-linux-imx , "daniel@ffwll.ch" , "mark.rutland@arm.com" , "festevam@gmail.com" , "s.hauer@pengutronix.de" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org Hi Robert, On Fri, Jul 12, 2019 at 08:15:32AM +0000, Robert Chiras wrote: > Hi Guido, > > On Jo, 2019-07-11 at 17:04 +0200, Guido Günther wrote: > > Hi Robert, > > On Wed, Jun 26, 2019 at 04:32:08PM +0300, Robert Chiras wrote: > > > > > > This patch-set improves the use of eLCDIF block on iMX 8 SoCs (like > > > 8MQ, 8MM > > > and 8QXP). Following, are the new features added and fixes from > > > this > > > patch-set: > > > > > > 1. Add support for drm_bridge > > > On 8MQ and 8MM, the LCDIF block is not directly connected to a > > > parallel > > > display connector, where an LCD panel can be attached, but instead > > > it is > > > connected to DSI controller. Since this DSI stands between the > > > display > > > controller (eLCDIF) and the physical connector, the DSI can be > > > implemented > > > as a DRM bridge. So, in order to be able to connect the mxsfb > > > driver to > > > the DSI driver, the support for a drm_bridge was needed in mxsfb > > > DRM > > > driver (the actual driver for the eLCDIF block). > > So I wanted to test this but with both my somewhat cleaned up nwl > > driverı and the nwl driver forward ported from the nxp vendor tree > > I'm > > looking at a black screen with current mainline - while my dcss > > forward > > port gives me nice output on mipi dsi. Do you have a tree that uses > > mipi > > dsi on imx8mq where I could look at to check for differences? > Somewhere on the pixel path (between the display controller and the > DSI) there is a block that inverts the polarity. I can't remember > exactly what was the role of this block, but the polarity is inverted > when eLCDIF is used in combination with the DSI. > If you take a look at my DSI driver from NXP releases (I guess you have > them), you will see there is a hack in mode_fixup: > > unsigned int *flags = &mode->flags; > if (dsi->sync_pol { > *flags |= DRM_MODE_FLAG_PHSYNC; > *flags |= DRM_MODE_FLAG_PVSYNC; > *flags &= ~DRM_MODE_FLAG_NHSYNC; > *flags &= ~DRM_MODE_FLAG_NVSYNC; > } else { > *flags &= ~DRM_MODE_FLAG_PHSYNC; > *flags &= ~DRM_MODE_FLAG_PVSYNC; > *flags |= DRM_MODE_FLAG_NHSYNC; > *flags |= DRM_MODE_FLAG_NVSYNC; > } Thanks for the suggestion! I'll try that. > > I know it's not clean, but it works for now. You can try this in your > driver and see if it helps. > These days I will also take your nwl-dsi driver and test it, and also > add support for bridge and eLCDIF to see if I can make it work. I have hacky bridge support over here already. Give me some days to clean it up and it might safe you some work. Cheers, -- Guido