Re: [PATCH] base: Change power/wakeup output from "" to "unsupported" if wakeup feature isn't supported by a device

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 2008-01-07 at 02:57 +0100, Rafael J. Wysocki wrote:
> On Monday, 7 of January 2008, Yi Yang wrote:
> > On Fri, 2008-01-04 at 08:09 -0800, David Brownell wrote:
> > > > > This patch changes empty output to "unsupported" in order that a user knows
> > > > > wakeup feature isn't supported by this device when he/she
> > > > > 'cat /sys/devices/.../power/wakeup', please consider to apply,
> > > > > thanks.
> > > >
> > > > What about simply removing "wakuep" file if wakeup is not supported?
> > > 
> > > It may not *stay* unsupported, so I think changing it in either
> > > of those permanent ways would be confusing/misleading.
> > > 
> > > For example, USB devices have multiple states ... minimally, an
> > > unconfigured state, and a configured state.  Some have multiple
> > > configurations.  Only configured states can be wakeup-capable.
> > > So a given device might have three states, but support wakeup
> > > except in one of them...
> > If so, we can change "unsupported" to "unconfigurable" or "inoperable"
> > which can cover the states "unconfigured", "unsupported" and other
> > unknown states. :-).
> 
> The main problem with your patch is that is changes a documented behavior
> visible by the user space.  That should be done very cautiously.
Which applications are using this interface? if they assume "\n" means
the unconfigurable or unavailable state, this is very fragile.
> 
> Thanks,
> Rafael

_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm

[Index of Archives]     [Linux ACPI]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [CPU Freq]     [Kernel Newbies]     [Fedora Kernel]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux