linux-kernel - [PATCH] drm/exynos/hdmi: Don't print error on deferral due to regulators

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Date:	Thu, 21 Apr 2016 14:51:38 -0400
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	linux-kernel@...r.kernel.org
Cc:	Kukjin Kim <kgene@...nel.org>, linux-samsung-soc@...r.kernel.org,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	dri-devel@...ts.freedesktop.org, Inki Dae <inki.dae@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	David Airlie <airlied@...ux.ie>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Javier Martinez Canillas <javier@....samsung.com>
Subject: [PATCH] drm/exynos/hdmi: Don't print error on deferral due to regulators

The regulators may not be available just because their driver's probe
function was just not executed and so the regulators not registered.

So, in this case the Exynos HDMI driver should not print logs since
a -EPROBE_DEFER is not really an error and that will just pollute
the kernel log and confuse users.

This patch prevents the following misleading messages to be printed:

[    1.443638] [drm:hdmi_probe] *ERROR* failed to get regulators
[    1.449326] [drm:hdmi_probe] *ERROR* hdmi_resources_init failed

Reported-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>

---

The real fix for these kind of issues is to change the device model
core to support device dependencies so the number of probe deferral
should be minimal or non-existent, instead of fixing on each driver.

But there have been different attempts [0,1] to implement this and
there doesn't seem that this will be solved in the short term.

[0]: https://lkml.org/lkml/2014/5/12/452
[1]: https://lkml.org/lkml/2015/5/25/251

 drivers/gpu/drm/exynos/exynos_hdmi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index e148d728e28c..dcac78b8aa16 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -1728,7 +1728,8 @@ static int hdmi_resources_init(struct hdmi_context *hdata)
 	}
 	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(supply), hdata->regul_bulk);
 	if (ret) {
-		DRM_ERROR("failed to get regulators\n");
+		if (ret != -EPROBE_DEFER)
+			DRM_ERROR("failed to get regulators\n");
 		return ret;
 	}
 
@@ -1852,7 +1853,8 @@ static int hdmi_probe(struct platform_device *pdev)
 
 	ret = hdmi_resources_init(hdata);
 	if (ret) {
-		DRM_ERROR("hdmi_resources_init failed\n");
+		if (ret != -EPROBE_DEFER)
+			DRM_ERROR("hdmi_resources_init failed\n");
 		return ret;
 	}
 
-- 
2.5.5