On Mon, Jan 30, 2017 at 12:37:14PM -0800, Daniel Walker wrote: > Hi, > > Cisco recently upgraded to kernel 4.4.. We have applications which use the > /sys interfaces for some hmon drivers. > We found that the following patches, > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bab2243ce1897865e31ea6d59b0478391f51812b > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c3b7cddc70075d525db6b3068d8b2b9158eedc84 > > Altered the interface as seen from userspace. These patches changed the paths > in the following way, > > Before, > /sys/bus/i2c/devices/14-0050/ > > After, > /sys/bus/i2c/devices/14-0050/hwmon/hwmon7 >
Actually, the stable link to use would be /sys/class/hwmon/hwmon7 in both cases, and to check if the name attribute resides in hwmon7 or in hwmon7/device (which is the real change in your case - it moved from hwmon7/device to hwmon7, ie from the parent device to the hwmon device). > My impression was that /sys was suppose to be stable, and debugfs was > unstable. I'm not sure what the current guidelines are > for this, but we would request that hmon drivers maintain a stable interface > from /sys. This change has cause upgrade issues > for us which we would like to avoid in the future. > The key transition is the move from attaching the attributes to the parent device (here: the i2c device) to the hwmon device. libsensors handles this transition transparently; I assume you are not using it ? > A patch to add in a compatibility layer would be welcome. > A compatibility layer would have to link each attribute back to the parent device. Interesting idea, actually. I'll check if that is possible. Thanks, Guenter
