RE: [PATCH][v3] ACPI: Do not report _OSI("Darwin") when acpi_osi=!Darwin provided

[Chen, Yu C]

Hi Lv,
> -----Original Message-----
> From: Zheng, Lv
> Sent: Monday, February 22, 2016 4:56 PM
> To: Chen, Yu C; linux-acpi@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; lenb@xxxxxxxxxx;
> matthew.garrett@xxxxxxxxxx; andy.shevchenko@xxxxxxxxx
> Subject: RE: [PATCH][v3] ACPI: Do not report _OSI("Darwin") when
> acpi_osi=!Darwin provided
> 
> Hi,
> 
> > From: Chen, Yu C
> > Subject: RE: [PATCH][v3] ACPI: Do not report _OSI("Darwin") when
> > acpi_osi=!Darwin provided
> >
> >
> > > From: Zheng, Lv
> > > Subject: RE: [PATCH][v3] ACPI: Do not report _OSI("Darwin") when
> > > acpi_osi=!Darwin provided
> > >
> > > Hi, Yu
> > >
> > > > From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-
> > > > owner@xxxxxxxxxxxxxxx] On Behalf Of Chen Yu
> > > > Subject: [PATCH][v3] ACPI: Do not report _OSI("Darwin") when
> > > > acpi_osi=!Darwin provided
> > > >
> > > > Commit 7bc5a2bad0b8 ("ACPI: Support _OSI("Darwin") correctly")
> > > > always reports positive value when Apple hardware queries
> _OSI("Darwin").
> > > > But sometimes the users might want to tell the hardware they don't
> > > > need the Darwin feature, for example, users may leverage the
> > > > hardware to power off the Thunderbolt, by appending
> > > > acpi_osi=!Darwin in command line, thus Apple hardware regards it
> > > > as an incompatible OS X system, hence turns off the Thunderbolt.
> > > [Lv Zheng]
> > > Both this patch and the original commit that is from Matthew look
> > > wrong to me.
> > > IMO, the feature should be done with an entirely different approach.
> > > Without test, I'm not sure if my comment is helpful for you.
> > > So could you let me take over to fix this issue?
> > >
> > Yes, sure, thanks.
> [Lv Zheng]
> It looks to me, the original Matthew's commit was trying to make the world
> easier with "acpi_osi=! acpi_osi=Darwin".
> While it finally adds limitation to the acpi_osi= quirk mechanism and is proven
> to be a bad idea.
> So why don't we just revert that commit?
> 
> According to my understanding, there is no better choice other than letting
> users to choose a non-recent-Windows OS that the kernel should pretend to
> be.
> So that kernel can stay simple to just pretend to be "recent-Windows".
> 
> And the only improvement that is acceptable in this case is:
> We can allow acpi_osi=Darwin to be equivalent to "acpi_osi=!
> acpi_osi=Darwin".
[Yu] Do you mean the new version be:
1. revert orginal 'OSI Darwin support' patch
2. improve acpi_osi=Linux/Darwin, automatically do acpi_osi=! for them
   (though we need to add entry in acpi_default_supported_interfaces)

yu