From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonard Crestez Subject: Re: [PATCH v3 4/5] drm: convert drivers to use drm_of_find_panel_or_bridge Date: Tue, 9 May 2017 17:28:21 +0300 Message-ID: <1494340101.24555.37.camel@nxp.com> References: <20170322132608.17353-1-robh@kernel.org> <20170322132608.17353-5-robh@kernel.org> <1490194865.2285.43.camel@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1490194865.2285.43.camel@pengutronix.de> Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring , Philipp Zabel Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Cristina Ciocan , Octavian Purdila List-Id: dri-devel@lists.freedesktop.org On Wed, Mar 22, 2017 at 5:01 PM, Philipp Zabel wrote: > On Wed, 2017-03-22 at 08:26 -0500, Rob Herring wrote: > > > > Similar to the previous commit, convert drivers open coding OF graph > > parsing to use drm_of_find_panel_or_bridge instead. > > > > This changes some error messages to debug messages (in the graph core). > > Graph connections are often "no connects" depending on the particular > > board, so we want to avoid spurious messages. Plus the kernel is not a > > DT validator. > > > > Signed-off-by: Rob Herring > > Reviewed-by: Archit Taneja > Tested-by: Philipp Zabel > (imx-ldb on i.MX6) It seems that this breaks on (at least) imx6qdl-sabreauto. The relevant section of the boot log looks like this: imx-drm display-subsystem: bound imx-ipuv3-crtc.2 (ops ipu_crtc_ops) imx-drm display-subsystem: bound imx-ipuv3-crtc.3 (ops ipu_crtc_ops) dwhdmi-imx 120000.hdmi: Detected HDMI TX controller v1.31a with HDCP (DWC HDMI 3D TX PHY) dwhdmi-imx 120000.hdmi: registered DesignWare HDMI I2C bus driver imx-drm display-subsystem: bound 120000.hdmi (ops dw_hdmi_imx_ops) imx-drm display-subsystem: failed to bind 2000000.aips-bus:ldb (ops imx_ldb_ops): -19 imx-drm display-subsystem: master bind failed: -19 It seems that imx6qdl-sabreauto does not have any panel defined in dts. This used to be ignored when of_graph_get_endpoint_by_regs returned NULL but now drm_of_find_panel_or_bridge returns -ENODEV and this causes imx_ldb_bind to fail altogether. Defining a panel works (including showing stuff on a LVDS panel). Ignoring -ENODEV also fixes this: --- drivers/gpu/drm/imx/imx-ldb.c +++ drivers/gpu/drm/imx/imx-ldb.c @@ -673,7 +673,7 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)                 ret = drm_of_find_panel_or_bridge(child,                                                   imx_ldb->lvds_mux ? 4 : 2, 0,                                                   &channel->panel, &channel->bridge); -               if (ret) +               if (ret != -ENODEV)                         return ret;                   /* panel ddc only if there is no bridge */ I don't know much about drm and it's not clear if failing to find a panel should be an error here or not and the hack above is likely the wrong way to handle it anyway. I was bisecting the fact that suspend now breaks on upstream. The fact that a probe error later breaks suspend is possibly an unrelated issue, right? --  Regards, Leonard