Some usb devices do not have drivers that support autosuspend. These drivers should not be added to the list of tunables, because toggling their good/bad value does nothing. Signed-off-by: Nanley Chery <nanleychery(a)gmail.com&gt; --- src/tuning/tuningusb.cpp | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/src/tuning/tuningusb.cpp b/src/tuning/tuningusb.cpp index 27a6dca..ee86335 100644 --- a/src/tuning/tuningusb.cpp +++ b/src/tuning/tuningusb.cpp @@ -28,6 +28,7 @@ #include "unistd.h" #include "tuningusb.h" #include <string.h> +#include <dirent.h> #include <utility> #include <iostream> #include <fstream> @@ -126,6 +127,25 @@ static void add_usb_callback(const char *d_name) if (access(filename, R_OK)!=0) return; + /* every interface of this device should support autosuspend */ + sprintf(filename, "/sys/bus/usb/devices/%s", d_name); + DIR *dir = opendir(filename); + if (!dir) + return; + while (1) { + struct dirent *entry = readdir(dir); + if (!entry) + break; + if (entry->d_name[0] == '.') + continue; + sprintf(filename, "/sys/bus/usb/devices/%s/%s/supports_autosuspend", d_name, entry->d_name); + bool intf_path_found; + bool intf_supports_auto = read_sysfs(filename, &intf_path_found); + if (intf_path_found && !intf_supports_auto) + return; + } + closedir(dir); + sprintf(filename, "/sys/bus/usb/devices/%s", d_name); usb = new class usb_tunable(filename, d_name); all_tunables.push_back(usb); -- 2.0.4