On Tue, Apr 24, 2018 at 9:03 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> Hi All,
>
> On 17-04-18 18:23, Hans de Goede wrote:
>>
>> Commit 5928c281524f ("ACPI / video: Default lcd_only to true on Win8-ready
>> and newer machines") made only_lcd default to true on all machines where
>> acpi_osi_is_win8() returns true, including laptops.
>>
>> The purpose of this is to avoid the bogus / non-working acpi backlight
>> interface which many newer BIOS-es define on desktop machines.
>>
>> But this is causing a regression on some laptops, specifically on the
>> Dell XPS 13 2013 model, which does not have the LCD flag set for its
>> fully functional ACPI backlight interface.
>>
>> Rather then DMI quirking our way out of this, this commits changes the
>> logic for setting only_lcd to true, to only do this on machines with
>> a desktop (or server) dmi chassis-type.
>>
>> Note that we cannot simply only check the chassis-type and not register
>> the backlight interface based on that as there are some laptops and
>> tablets which have their chassis-type set to "3" aka desktop. Hopefully
>> the combination of checking the LCD flag, but only on devices with
>> a desktop(ish) chassis-type will avoid the needs for DMI quirks for this,
>> or at least limit the amount of DMI quirks which we need to a minimum.
>>
>> Cc: James Hogan <jhogan@xxxxxxxxxx>
>> Reported-and-tested-by: James Hogan <jhogan@xxxxxxxxxx>
>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>
>
> Commit 5928c281524f has been cherry=picked into 4.15.17 and now is causing
> problems for more users it seems:
> https://bugzilla.redhat.com/show_bug.cgi?id=1571036
>
> Rafael, can we get this merged into 4.17-rc# please, with a fixed /
> Cc stable added ?
I've queued it up, but I'm sort of negatively impressed by this.
Thanks,
Rafael
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