From 7bf727ae0ff8cfcd7f99c6039a0a9caac1978f25 Mon Sep 17 00:00:00 2001
From: Dmitry Osipenko <digetx@gmail.com>
Date: Tue, 8 Feb 2022 00:29:23 +0300
Subject: drm/tegra: Use dev_err_probe()
Git-commit: f07f04a51d92165e0ad711f1be1cc5bbbfcb4766
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Replace dev_printk() with a generic dev_err_probe() helper which silences
noisy error messages about deferred probe and makes easy to debug failing
deferred probe by printing notification about the failure to KMSG in the
end of kernel booting process and by adding failing device and the reason
of deferred probe to devices_deferred of debugfs. This was proven to be
useful in the case of eDP driver regression by immediately showing why
display driver was failing when user asked for help, otherwise it would've
been much more difficult to debug such problems on a third party device
that doesn't have developer setup.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/tegra/dc.c   | 13 +++----------
 drivers/gpu/drm/tegra/hdmi.c | 34 +++++++++-------------------------
 2 files changed, 12 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index eb70eee8992a..9435c867c865 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -3211,16 +3211,9 @@ static int tegra_dc_probe(struct platform_device *pdev)
 		return -ENXIO;
 
 	err = tegra_dc_rgb_probe(dc);
-	if (err < 0 && err != -ENODEV) {
-		const char *level = KERN_ERR;
-
-		if (err == -EPROBE_DEFER)
-			level = KERN_DEBUG;
-
-		dev_printk(level, dc->dev, "failed to probe RGB output: %d\n",
-			   err);
-		return err;
-	}
+	if (err < 0 && err != -ENODEV)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to probe RGB output\n");
 
 	platform_set_drvdata(pdev, dc);
 	pm_runtime_enable(&pdev->dev);
diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
index 8845af5d325f..bf240767dad9 100644
--- a/drivers/gpu/drm/tegra/hdmi.c
+++ b/drivers/gpu/drm/tegra/hdmi.c
@@ -1775,7 +1775,6 @@ static irqreturn_t tegra_hdmi_irq(int irq, void *data)
 
 static int tegra_hdmi_probe(struct platform_device *pdev)
 {
-	const char *level = KERN_ERR;
 	struct tegra_hdmi *hdmi;
 	struct resource *regs;
 	int err;
@@ -1817,36 +1816,21 @@ static int tegra_hdmi_probe(struct platform_device *pdev)
 
 	hdmi->hdmi = devm_regulator_get(&pdev->dev, "hdmi");
 	err = PTR_ERR_OR_ZERO(hdmi->hdmi);
-	if (err) {
-		if (err == -EPROBE_DEFER)
-			level = KERN_DEBUG;
-
-		dev_printk(level, &pdev->dev,
-			   "failed to get HDMI regulator: %d\n", err);
-		return err;
-	}
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to get HDMI regulator\n");
 
 	hdmi->pll = devm_regulator_get(&pdev->dev, "pll");
 	err = PTR_ERR_OR_ZERO(hdmi->pll);
-	if (err) {
-		if (err == -EPROBE_DEFER)
-			level = KERN_DEBUG;
-
-		dev_printk(level, &pdev->dev,
-			   "failed to get PLL regulator: %d\n", err);
-		return err;
-	}
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to get PLL regulator\n");
 
 	hdmi->vdd = devm_regulator_get(&pdev->dev, "vdd");
 	err = PTR_ERR_OR_ZERO(hdmi->vdd);
-	if (err) {
-		if (err == -EPROBE_DEFER)
-			level = KERN_DEBUG;
-
-		dev_printk(level, &pdev->dev,
-			   "failed to get VDD regulator: %d\n", err);
-		return err;
-	}
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to get VDD regulator\n");
 
 	hdmi->output.dev = &pdev->dev;
 
-- 
2.38.1