Re: [Powertop] [PATCH v2 1/1] tunables: check usb autosuspend support before add

[Alexandra Yates <alexandra.yates at linux.intel.com>]

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> 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>
> ---
>
> Fixed the issue in the previous patch that allowed returning between
> opendir and closedir (thanks Sergey). Also improve detection of interface
> folders.
>
>  src/tuning/tuningusb.cpp | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/src/tuning/tuningusb.cpp b/src/tuning/tuningusb.cpp
> index 27a6dca..d2a0c11 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>
> @@ -117,6 +118,7 @@ static void add_usb_callback(const char *d_name)
>  {
>  	class usb_tunable *usb;
>  	char filename[4096];
> +	DIR *dir;
>
>  	sprintf(filename, "/sys/bus/usb/devices/%s/power/control", d_name);
>  	if (access(filename, R_OK) != 0)
> @@ -126,6 +128,23 @@ 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);
> +	if ((dir = opendir(filename))) {
> +		struct dirent *entry;
> +		while ((entry = readdir(dir))) {
> +			/* dirname: <busnum>-<devnum>...:<config num>-<interface num> */
> +			if (!isdigit(entry->d_name[0]))
> +				continue;
> +			sprintf(filename, "/sys/bus/usb/devices/%s/%s/supports_autosuspend",
> d_name, entry->d_name);
> +			if (access(filename, R_OK) == 0 && read_sysfs(filename) == 0)
> +				break;
> +		}
> +		closedir(dir);
> +		if (entry)
> +			return;
> +	}
> +
>  	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
>
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>

Nanley,

Thank you very much for sending you patch. It was up-streamed today.

Alexandra.