On Mon, Sep 25, 2017 at 05:46:54PM +0000, Mario.Limonciello@xxxxxxxx wrote: > > -----Original Message----- > > From: Andy Shevchenko [mailto:andy.shevchenko@xxxxxxxxx] > > Sent: Monday, September 25, 2017 12:58 PM > > To: Pali Rohár <pali.rohar@xxxxxxxxx> > > Cc: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; dvhart@xxxxxxxxxxxxx; > > LKML <linux-kernel@xxxxxxxxxxxxxxx>; Platform Driver <platform-driver- > > x86@xxxxxxxxxxxxxxx>; quasisec@xxxxxxxxxx > > Subject: Re: [PATCH 11/12] platform/x86: dell-wmi-smbios: introduce character > > device for userspace > > > > On Mon, Sep 25, 2017 at 7:31 PM, Pali Rohár <pali.rohar@xxxxxxxxx> wrote: > > > On Thursday 21 September 2017 08:57:16 Mario Limonciello wrote: > > >> This userspace character device will be used to perform SMBIOS calls > > >> from any applications sending a properly formatted 4k calling interface > > >> buffer. > > >> > > >> This character device is intended to deprecate the dcdbas kernel module > > >> and the interface that it provides to userspace. > > >> > > >> It's important for the driver to provide a R/W ioctl to ensure that > > >> two competing userspace processes don't race to provide or read each > > >> others data. > > > > >> +What: /dev/wmi-dell-wmi-smbios > > > > > > What about just /dev/dell-smbios? IOCTL provided here is just SMBIOS > > > related and I think userspace does not have to care if it is via WMI or > > > direct SMM mode... Important is that it provides character device for > > > SMBIOS API and not how it is implemented. I agree with this point, the implementation (WMI under the covers) is not relevant. That said, this is an example of exposing WMI functionality to userspace, and I DO NOT want to have a naming discussion for every single WMI GUID that we choose to expose. > > > > > > Anyway, Darren, Andy, do we have some convention for naming platform > > > character devices? > > > > For me, looking to this case, seems better to expose a folder like > > /dev/smbios/ > > with actual vendor device nodes inside like > > /dev/smbios/dell > > I disagree with this. Dell exposes smbios calling in this kernel interface but > other vendor drivers may also expose different methods for character devices > that are not SMBIOS. > > I'm envisioning that this is just the first kernel module that will use a WMI > character device to userspace. That's why I wanted to use a generic namespace. > > I would say it could be /dev/wmi-$GUID or /dev/wmi/$driver-$GUID if you want > something more generic. > As long as it's discovereable from uevent that's fine to me. > > > > > Darren? I would like to see an automated and definiitive way to export WMI GUIDs. Something we can look at, compare to a set of rules, and say yay/nay. From that perspective, I like Mario's general proposal. It is not clear to me if the $driver- prefix adds any value though - would we ever have need of DRIVER_X-GUID_A and DRIVER_Y-GUID_A ??? I'm thinking not. /dev/wmi/$GUID -- Darren Hart VMware Open Source Technology Center
