[Intel-gfx] [PATCH 3/4] drm/i915: use ACPI LID status for LVDS ->detect hook

[Jesse Barnes]

On Thu, 16 Jul 2009 09:54:44 +0800
ykzhao <yakui.zhao at intel.com> wrote:

> On Thu, 2009-07-16 at 06:11 +0800, Jesse Barnes wrote:
> > We can't load or hotplug detect LVDS like we can other outputs, but
> > if there's a lid device present we can use it as a proxy.  This
> > allows the LFP state to be determined at ->detect time, making
> > configurations requiring manual intervention today "just work"
> > assuming the lid device status is correct.
> It is ok that the LID status is to decide whether the LVDS is
> connected/disconnected.
> 
> But on some boxes the initial LID status is incorrect. It reports that
> LID is closed although it is open.
>     For example: 
>     http://bugzilla.kernel.org/show_bug.cgi?id=5809
>     http://bugzilla.kernel.org/show_bug.cgi?id=13263
>     http://bugzilla.kernel.org/show_bug.cgi?id=5904
>     https://bugs.launchpad.net/ubuntu/+bug/34389
> Maybe this feature is not supported on the above laptops. That means
> that LVDS is always connected regardless of LID status.
> 
> At the same time on some boxes there is no ACPI LID event when the LID
> is reopened. In such case we can't send the hotplug event to user
> space when the LID is reopened. How about disable this feature on
> such box? For example: Aspire One.
> 
> 
> I have another issue about the hotplug event.
> On some boxes it will continue to report the LID event  when the LID
> is closed. In such case we had better not send the hotplug event to
> user space. Otherwise the user space will receive too many hotplug
> event about LVDS. For example:
>      http://bugzilla.kernel.org/show_bug.cgi?id=10485
>      http://bugzilla.kernel.org/show_bug.cgi?id=5853
> 
> So it will be better that the feature of hotplug/LID status is not
> supported on such boxes.

Yeah those are all good points; thanks for the list of bugs.  Any
suggestions on how to do a blacklist?  Is there an ACPI or DMI
identifier we could use?

-- 
Jesse Barnes, Intel Open Source Technology Center