[PATCH] drm/i915: set LVDS connector status to unknown if the lid is closed

[Andrei Paskevich]

On Wed, Aug 11, 2010 at 3:32 PM, Adam Jackson <ajax at redhat.com> wrote:
> On Wed, 2010-08-11 at 01:16 +0200, Andrei Paskevich wrote:
>> Currently, the LVDS connector on i915-equipped laptops
>> is always reported as connected, regardless of the lid
>> state and presence of external monitors. This was done
>> because of too many BIOSes reporting lid status in
>> an unreliable way. However, in a quite usual setup of
>> a laptop attached to an external monitor, the only way
>> to obtain the monitor's resolution on boot is to disable
>> the LVDS via the boot command line, which is unfortunate
>> as one have to reboot to get the internal screen back.
>
> If ACPI lid status were even remotely reliable for Intel machines, this
> might be a good idea.

I don't agree: if lid status were reliable, there would be no need for this,
as we could just report a lid-closed LVDS disconnected (as it was done
in intel_lvds.c before). The trick with the "unknown" status is really useful
when ACPI erroneously reports the lid as closed and there are no other
connected monitors.

The purpose of the proposed patch is to provide a correct screen mode
on boot for those Intel laptops which have correct ACPI lid status handling
(and such laptops do exist) without changing the existing behaviour in
the default case.

Andrei