[PATCH v3] firmware: log name & outcome of loaded firmware

["Robin H. Johnson" <robbat2@gentoo.org>]

It's non-trivial to figure out names of firmware that was actually
loaded, add a debug statement at the end of _request_firmware that logs
the name & result of each firmware.

This is esp. valuable early in boot, before logging of UEVENT is
available.

v3:
- Log at dev_dbg level per maintainer.
- HOWTO: Enable at boot via kernel boot param
  dyndbg="func _request_firmware +p"
- Credit to Drew DeVault for parallel creation and help promoting the
  idea.

Alternate-Creation: Drew DeVault <sir@cmpwn.com>
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
---
 drivers/base/firmware_loader/main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index bf44c79beae9..84a879608ca4 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -791,6 +791,13 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 		fw = NULL;
 	}
 
+	/* Provide a consistent way to capture the result of trying to load any
+	 * firmware. As a potential future improvement, this might include
+	 * persistent state that firmware is loaded (or failed to load for some
+	 * reason). See Message-ID: <20191113205010.GY11244@42.do-not-panic.com>
+	 * for background */
+	dev_dbg(device, "%s %s ret=%d\n", __func__, name, ret);
+
 	*firmware_p = fw;
 	return ret;
 }
-- 
2.24.0