On Wed, Oct 18, 2017 at 06:10:58PM +0300, Ville Syrjälä wrote: > On Tue, Sep 26, 2017 at 06:49:08AM +0200, Michał Kępień wrote: > > > > call call_fext_func() with a NULL device. Let's just skip those > > > > function calls when the FUJ02E3 device is not present. > > > > > > > > > > Interesting. We call call_fext_func from many locations using the > > > "device" argument, or the driver static "fext". > > > > > > This looks to me that we should be a bit more consistent here. > > > > This is intentional. The plan was to extract the backlight part of > > fujitsu-laptop into a separate module, fujitsu-backlight, which would > > use a simple two-function API exposed by fujitsu-laptop to control LCD > > backlight power. Those functions would have to somehow access the > > FUJ02E3 ACPI device while not being ACPI callbacks. Thus, fext is > > storing a pointer to the last (and most likely only) instantiated > > FUJ02E3 ACPI device so that it can be used for setting LCD backlight > > power from fujitsu-backlight. See commit ca0d9eab0fb5 for a brief > > discussion of why this solution was chosen. > > > > > Finally, it seems a proper fix would be to either not register the > > > backlight device if !fext or to check for !fext inside call_fext_func. > > > > My draft patch series which splits off fujitsu-backlight includes the > > NULL check for fext inside the functions exposed by fujitsu-laptop. > > Sadly, I have not got round to submitting it yet. > > > > Just to make sure we are all on the same page here, please note that > > access to FUJ02E3 is only needed for controlling LCD backlight _power_, > > not LCD backlight _brightness_. > > > > Speaking of which, I just noticed that my S7020 can control its LCD > > brightness just fine without fujitsu-laptop being loaded. Heck, it even > > works when booted with "noacpi". It seems to me that on this model, LCD > > brightness control works at the firmware level and an ACPI-based driver > > is just another possible way of getting/setting LCD brightness level. > > Jonathan, IIRC you have an S7020 as well, could you please test that? > > You know better than me why this driver was needed in the first place. > > > > Ville, could you please test your S6120 for the above as well? Please > > try unloading/blacklisting fujitsu-laptop and see whether LCD backlight > > control still works. > > My recollection is that the Fn+brightness works even without the > driver. But I'll try to retest that tonight since I'm not 100% sure. Indeed that is the case. > > > > > Finally, it seems the S6120 also has a row of "application panel" > > hotkeys above the keyboard, but lacks the FUJ02E3 ACPI device, so I am > > wondering whether these hotkeys work in Linux. Ville, do they? > > They work via the apanel driver. Well, there's buttons 1-4 and Enter. > Buttons 1-4 work but the Enter doesn't, but that could be just an > oversight in the apanel driver. That's at least how the S6010 works. > I'll have to retest the S6120 to make sure it behaves the same way. > At least it has the same set of buttons on it. Looks like S6120 works the same way, via the apanel driver. -- Ville Syrjälä Intel OTC
