battery: do not report sysfs ENODEV failure

Linux reports ENODEV if the reported battery values are equal to
ACPI_BATTERY_VALUE_UNKNOWN. This can be observed for an unpatched Clevo
B7130 laptop while reading the "Battery Present Charge" attribute.

Since this is a non-fatal, non-recoverable event, do not report such
errors. Also change the error message to report the filename triggering
this error to ease hunting down the error.

diff --git a/src/battery.c b/src/battery.c
index f106da09bd4e2114cc82c2fb84de806a2db21960..9b060dd9286cc692f03cd8205121868fe0f786ae 100644 (file)
--- a/src/battery.c
+++ b/src/battery.c
@@ -416,10 +416,13 @@ static int sysfs_file_to_buffer(char const *dir, /* {{{ */
 
        if (fgets (buffer, buffer_size, fp) == NULL)
        {
-               char errbuf[1024];
                status = errno;
-               WARNING ("battery plugin: fgets failed: %s",
-                               sstrerror (status, errbuf, sizeof (errbuf)));
+               if (status != ENODEV)
+               {
+                       char errbuf[1024];
+                       WARNING ("battery plugin: fgets (%s) failed: %s", filename,
+                                       sstrerror (status, errbuf, sizeof (errbuf)));
+               }
                fclose (fp);
                return status;
        }