On 4/10/2023 3:43 PM, Jonathan Corbet wrote:
Florian Fainelli <f.fainelli@xxxxxxxxx> writes:
Newline characters will be taken into account for the firmware search
path parameter, warn users about that and provide an example using 'echo
-n' such that it clarifies the typical use of that parameter.
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
Documentation/driver-api/firmware/fw_search_path.rst | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/Documentation/driver-api/firmware/fw_search_path.rst b/Documentation/driver-api/firmware/fw_search_path.rst
index a360f1009fa3..d7cb1e8f0076 100644
--- a/Documentation/driver-api/firmware/fw_search_path.rst
+++ b/Documentation/driver-api/firmware/fw_search_path.rst
@@ -22,5 +22,10 @@ can use the file:
* /sys/module/firmware_class/parameters/path
-You would echo into it your custom path and firmware requested will be
-searched for there first.
+You would echo into it your custom path and firmware requested will be searched
+for there first. Be aware that newline characters will be taken into account
+and may not produce the intended effects. For instance you might want to use:
+
+echo -n /path/to/script > /sys/module/firmware_class/parameters/path
+
+to ensure that your script is being used.
So I have no problem with applying this, but I have to ask...might it
not be better to fix the implementation of that sysfs file to strip
surrounding whitespace from the provided path? This patch has the look
of a lesson learned the hard way; rather than codifying this behavior
into a feature, perhaps we could just make the next person's life a bit
easier...?
I was not sure whether it was on purpose or not, Greg, will we break
anyone's use case if we strip off \n from the firmware path passed via
sysfs?
--
Florian
