On Friday 23 February 2018 22:17:30 Andy Shevchenko wrote: > On Fri, 2018-02-23 at 19:53 +0000, Mario.Limonciello@xxxxxxxx wrote: > > > > > Marco (CC'ed) privately emailed Pali and I to discuss an issue > > > > that > > > > dell-laptop > > > > wasn't working properly for him and dell-smbios couldn't find a > > > > backend. > > > > > > > > I thought at first it was an issue of the race condition recently > > > > discussed but > > > > it's actually a case that the distro kernel he's using compiled: > > > > > > > > DELL_SMBIOS > > > > DELL_LAPTOP > > > > > > > > But didn't select DELL_SMBIOS_WMI or DELL_SMBIOS_SMM. > > > > > > Distros have to enable whatever they want to. > > > > At least in this instance I'd hypothesize it's because these are new > > config > > options that default to off. > > > > They probably had DELL_SMBIOS enabled before and carried that forward > > But there was nothing to transition them to make them turn on > > DELL_SMBIOS_WMI or DELL_SMBIOS_SMM. > > So, the driver requires now _at least_ one of the backend enabled? Basically driver can be compiled with zero backends. But then every one request would fail and I do not see any reason why somebody want such combination on real hardware. To make dell_smbios.ko work we need *correct* backend to be loaded. For laptops >= 2017 it is needed dell_smbios_wmi.ko, For laptops <= 2007 it is needed dell_smbios_smm.ko and for remaining both should work. > > > Can it be the Dell model, that survives w/o one of above or even > > > both? > > > > The design as it exists to day is that dell-laptop needs dell-smbios > > but > > dell-smbios won't run unless it has a backend selected. > > How was it before? Before there was only dell_smbios_smm.ko and was part of dell_smbios.ko. Now when SMM API started to be deprecated and stopped to work on new laptops, it was needed to write new backend driver. > > Something like this maybe then to not let them even try to run dell- > > smbios? > > Wouldn't be a regression still? > > P.S. See also the link I answered with to Pali. > -- Pali Rohár pali.rohar@xxxxxxxxx
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