linux-kernel - [PATCH v1 1/1] drm: mxsfb: Silence -EPROBE

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Message-Id: <d5761eb871adde5464ba112b89d966568bc2ff6c.1608020391.git.agx@sigxcpu.org>
Date:   Tue, 15 Dec 2020 09:23:38 +0100
From:   Guido Günther <agx@...xcpu.org>
To:     Marek Vasut <marex@...x.de>, Stefan Agner <stefan@...er.ch>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Emil Velikov <emil.l.velikov@...il.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/1] drm: mxsfb: Silence -EPROBE_DEFER while waiting for bridge

It can take multiple iterations until all components for an attached DSI
bridge are up leading to several:

[    3.796425] mxsfb 30320000.lcd-controller: Cannot connect bridge: -517
[    3.816952] mxsfb 30320000.lcd-controller: [drm:mxsfb_probe [mxsfb]] *ERROR* failed to attach bridge: -517

Silence this by checking for -EPROBE_DEFER and using dev_err_probe() so
we set a deferred reason in case a dependency fails to probe (which
quickly happens on small config/DT changes due to the rather long probe
chain which can include bridges, phys, panels, backights, leds, etc.).

This also removes the only DRM_DEV_ERROR() usage, the rest of the driver
uses dev_err().

Signed-off-by: Guido Günther <agx@...xcpu.org>
Fixes: c42001e357f7 ("drm: mxsfb: Use drm_panel_bridge")
---
 drivers/gpu/drm/mxsfb/mxsfb_drv.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 6faf17b6408d..6da93551e2e5 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -134,11 +134,8 @@ static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
 		return -ENODEV;
 
 	ret = drm_bridge_attach(&mxsfb->encoder, bridge, NULL, 0);
-	if (ret) {
-		DRM_DEV_ERROR(drm->dev,
-			      "failed to attach bridge: %d\n", ret);
-		return ret;
-	}
+	if (ret)
+		return dev_err_probe(drm->dev, ret, "Failed to attach bridge\n");
 
 	mxsfb->bridge = bridge;
 
@@ -212,7 +209,8 @@ static int mxsfb_load(struct drm_device *drm,
 
 	ret = mxsfb_attach_bridge(mxsfb);
 	if (ret) {
-		dev_err(drm->dev, "Cannot connect bridge: %d\n", ret);
+		if (ret != -EPROBE_DEFER)
+			dev_err(drm->dev, "Cannot connect bridge: %d\n", ret);
 		goto err_vblank;
 	}
 
-- 
2.29.2