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SubjectRe: [PATCH 2/2] Revert "ACPI / button: Change default behavior to lid_init_state=open"
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On Friday, May 12, 2017 02:36:20 AM Zheng, Lv wrote:
> Hi,
>
> > From: Benjamin Tissoires [mailto:benjamin.tissoires@redhat.com]
> > Subject: Re: [PATCH 2/2] Revert "ACPI / button: Change default behavior to lid_init_state=open"
> >
> > On May 11 2017 or thereabouts, Zheng, Lv wrote:
> > > Hi,
> > >
> > > > From: Benjamin Tissoires [mailto:benjamin.tissoires@redhat.com]
> > > > Subject: [PATCH 2/2] Revert "ACPI / button: Change default behavior to lid_init_state=open"
> > > >
> > > > This reverts commit 77e9a4aa9de10cc1418bf9a892366988802a8025.
> > > >
> > > > Even if the method implementation can be buggy on some platform,
> > > > the "open" choice is worse. It breaks docking stations basically
> > > > and there is no way to have a user-space hwdb to fix that.
> > > >
> > > > On the contrary, it's rather easy in user-space to have a hwdb
> > > > with the problematic platforms. Then, libinput (1.7.0+) can fix
> > > > the state of the LID switch for us: you need to set the udev
> > > > property LIBINPUT_ATTR_LID_SWITCH_RELIABILITY to 'write_open'.
> > > >
> > > > When libinput detects internal keyboard events, it will
> > > > overwrite the state of the switch to open, making it reliable
> > > > again. Given that logind only checks the LID switch value after
> > > > a timeout, we can assume the user will use the internal keyboard
> > > > before this timeout expires.
> > > >
> > > > For example, such a hwdb entry is:
> > > >
> > > > libinput:name:*Lid Switch*:dmi:*svnMicrosoftCorporation:pnSurface3:*
> > > > LIBINPUT_ATTR_LID_SWITCH_RELIABILITY=write_open
> > >
> > > For the reason mentioned previously and proofs here (see patch descriptions):
> > > https://patchwork.kernel.org/patch/9717111/
> >
> > I am not sure you can call this proofs. The "close" state is IMO the
> > exact same as the "method" one, it's just that the intel driver
> > triggers the evaluation of the _LID method, not acpi/button.c.
>
> I should correct you that:
> 1. intel_lvds driver only evaluates _LID method for its own purpose,
> See my reply to PATCH 4-5;
> 2. acpi/button.c is still responsible for generating the lid input event (to input layer and thus the userspace)
> And the input event generated by button.c differs for the 2 modes.
> See my another reply to PATCH 02.
>
> >
> > And remember that this new default prevents userspace to fix it because
> > it's rather easy to detect that the device is actually opened (input
> > events coming from interanl keyboard, touchscreen, or touchpad), while
> > reporting the lid switch as open means we can't know if the user is
> > simply not using the internal devices, or if we have just a wrong state.
>
> That depends on what the meaning of "fix" is IMO.
> I saw you wrote a lot in another message, let's discuss this there.
>
> >
> > Given that this patch breaks all Lenovos with a dock (I can guess that 6
> > lines this year are using docks, and within each line you have 2-5
> > variants), I'd suggest we do not break those existing laptops and just
> > revert this patch.
> >
> > I would think other OEMs have a docking station with an actual power
> > button but I can't be sure by looking at the product pages.
>
> I'm not sure if it breaks the external monitor usage model.

Well, if it worked in a specific way that users depended on before the commit in
question and now it works differently, then it does break things.

Benjamin, my understanding is that this is the case, is it correct?

Thanks,
Rafael

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