Messages in this thread | | | Subject | Re: [PATCH 06/12] platform/x86: dell-wmi-smbios: Add a sysfs interface for SMBIOS tokens | From | Andy Lutomirski <> | Date | Wed, 27 Sep 2017 12:49:04 -0700 |
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On 09/27/2017 11:55 AM, Darren Hart wrote: > On Wed, Sep 27, 2017 at 09:31:47PM +0300, Andy Shevchenko wrote: >> On Wed, Sep 27, 2017 at 9:27 PM, <Mario.Limonciello@dell.com> 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? >
Not really. If this is indeed static data that is potentially useful for scripts and such, than sysfs is kind of nice.
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