linux-kernel - [PATCH] media: v4l: subdev: Use dev_err() to print errors and clarify

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Message-ID: <20241122153343.237308-1-demonsingur@gmail.com>
Date: Fri, 22 Nov 2024 17:33:39 +0200
From: Cosmin Tanislav <demonsingur@...il.com>
To: 
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	Hans Verkuil <hverkuil@...all.nl>,
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	Cosmin Tanislav <demonsingur@...il.com>,
	Paweł Anikiel <panikiel@...gle.com>,
	linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] media: v4l: subdev: Use dev_err() to print errors and clarify

The error values end up being returned to userspace, it makes sense to
have some useful information printed when debugging them, even if the
reason for the errors are bad configs or internal driver issues.

Replace dev_dbg() with dev_err() for errors.

Also, when using complex pipelines with multiple bridges between the
video device and multiple source sub devices, printing just the video
device name for each error does not provide enough context as to which
operation failed.

Add sub device entity name to the messages where possible to clarify the
source of the errors.

Signed-off-by: Cosmin Tanislav <demonsingur@...il.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 4f0eecd7fd66f..d51b4594d11c5 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -2303,20 +2303,21 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
 				    &found_streams, &enabled_streams);
 
 	if (found_streams != streams_mask) {
-		dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
+		dev_err(dev, "streams 0x%llx not found on %s:%u\n",
 			streams_mask & ~found_streams, sd->entity.name, pad);
 		ret = -EINVAL;
 		goto done;
 	}
 
 	if (enabled_streams) {
-		dev_dbg(dev, "streams 0x%llx already enabled on %s:%u\n",
+		dev_err(dev, "streams 0x%llx already enabled on %s:%u\n",
 			enabled_streams, sd->entity.name, pad);
 		ret = -EALREADY;
 		goto done;
 	}
 
-	dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
+	dev_dbg(dev, "enable streams %s:%u:%#llx\n",
+		sd->entity.name, pad, streams_mask);
 
 	already_streaming = v4l2_subdev_is_streaming(sd);
 
@@ -2333,8 +2334,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
 	}
 
 	if (ret) {
-		dev_dbg(dev, "enable streams %u:%#llx failed: %d\n", pad,
-			streams_mask, ret);
+		dev_err(dev, "enable streams %s:%u:%#llx failed: %d\n",
+			sd->entity.name, pad, streams_mask, ret);
 		goto done;
 	}
 
@@ -2403,20 +2404,21 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
 				    &found_streams, &enabled_streams);
 
 	if (found_streams != streams_mask) {
-		dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
+		dev_err(dev, "streams 0x%llx not found on %s:%u\n",
 			streams_mask & ~found_streams, sd->entity.name, pad);
 		ret = -EINVAL;
 		goto done;
 	}
 
 	if (enabled_streams != streams_mask) {
-		dev_dbg(dev, "streams 0x%llx already disabled on %s:%u\n",
+		dev_err(dev, "streams 0x%llx already disabled on %s:%u\n",
 			streams_mask & ~enabled_streams, sd->entity.name, pad);
 		ret = -EALREADY;
 		goto done;
 	}
 
-	dev_dbg(dev, "disable streams %u:%#llx\n", pad, streams_mask);
+	dev_dbg(dev, "disable streams %s:%u:%#llx\n",
+		sd->entity.name, pad, streams_mask);
 
 	if (!use_s_stream) {
 		/* Call the .disable_streams() operation. */
@@ -2432,8 +2434,8 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
 	}
 
 	if (ret) {
-		dev_dbg(dev, "disable streams %u:%#llx failed: %d\n", pad,
-			streams_mask, ret);
+		dev_err(dev, "disable streams %s:%u:%#llx failed: %d\n",
+			sd->entity.name, pad, streams_mask, ret);
 		goto done;
 	}
 
-- 
2.47.0