On Wed, Sep 27, 2017 at 09:31:47PM +0300, Andy Shevchenko wrote: > On Wed, Sep 27, 2017 at 9:27 PM, <Mario.Limonciello@xxxxxxxx> wrote: > > >> > > > Darren, Andy, any comments? I'm not quite sure if such API is suitable > >> > > > for long term in kernel. > >> > > > >> > > I would try to avoid sysfs interfaces for some particular devices. > >> > > Besides we are creating a character device. Would it be suitable there? > >> > > >> > If the character device having 2 different ioctls for different needs is > >> > acceptable I'm happy to adjust the series to do this instead. > >> > >> One piece of feedback I had re the char device was to see if we could avoid the > >> need for the IOCTL altogether, I'd like to have that discussion before we add > >> another. > > > > My original design was sysfs files for everything but it was raised by several folks > > that you run into the potential of two userspace processes stomping on each > > other's data when they run the ACPI call. That's why I need to have a mutex to > > protect and make sure that userspace calls get the right results. > > > > >> > > > Basically tokens are list of tuples <id, location, value> with > >> > > > possibility to active them, right? > >> > > > > >> > > >> > I didn't add a way to activate them through this, it was only for > >> > reading purpose. Activating them should be possible through the > >> > SMBIOS calling interface though. > >> > > >> > >> These are read-only as I understood it, and only with the right privileges. > >> Sysfs seemed appropriate for this to me. > > > > Andy S was against having this data as another sysfs file. From a userspace > > perspective I think it's simpler to just parse a sysfs file with read only static > > data as root. With the current ioctl based solution it requires userspace to run > > an ioctl to determine how many tokens exist, then allocate a chunk of memory > > big enough to hold all the token data and then run another ioctl to get all the tokens. > > > > Andy S, given this change between v1 and v2 what do you feel is better? > > I have no strong opinion on this. That's why I recommended to listen to Andy L. +Andy Lutomirski Andy L, any preference on your part regarding exporting these tokens via sysfs or through an additional IOCTL in the chardev? -- Darren Hart VMware Open Source Technology Center
