> -----Original Message----- > From: Pali Rohár [mailto:pali.rohar@xxxxxxxxx] > Sent: Thursday, April 13, 2017 8:51 AM > To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; Hans de Goede > <hdegoede@xxxxxxxxxx> > Cc: kernel@xxxxxxxxxx; dvhart@xxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; > len.brown@xxxxxxxxx; corentin.chary@xxxxxxxxx; luto@xxxxxxxxxx; > andriy.shevchenko@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; platform- > driver-x86@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx > Subject: Re: RFC: WMI Enhancements > > On Thursday 13 April 2017 13:29:41 Mario.Limonciello@xxxxxxxx wrote: > > > Please pardon my ignorance, but what do we actually gain by exposing > > > WMI to userspace? Enabling applications to fetch SMBIOS data? We > > > already have an interface for that. Enabling applications to receive input > events? Likewise. > > > > Input notifications are just one aspect that received over WMI. I > > don't see any reason to move the notifications out of the kernel. > > > > In terms of userspace applications, once a WMI interface to userspace > > is available libsmbios would change over to that. Applications using > libsmbios would benefit. > > Really libsmbios matters here? Hans (added to thread) wrote that libsmbios is > a relic, something of ages long gone by and a normal user should never use it. > A normal user shouldn't be using it directly, but libsmbios is used by a few open source tools as a dependency. It's also used in many Dell manageability tools. > If this is truth and libsmbios should not be used, then we probably do not need > to care about it in changes for WMI. > > Hans, Mario, any comment/clarification about it? > > > > You mentioned WMI's efficiency compared to SMI/SMM, but is it a > > > difference significant enough for anyone to notice? > > > > At least for Dell there are optimizations being made when data is > > requested over the WMI-ACPI wrapper instead of directly via SMI/SMM. > > > > For example if the data is a "static" table or the request is to > > something that is passed thru to the EC it's a big waste of effort to put the > CPU in SMM. > > > > The savings there is significant. > > Maybe we can use this Dell WMI-ACPI wrapper for kernel drivers instead of > current SMI/SMM direct access? > > -- > Pali Rohár > pali.rohar@xxxxxxxxx
