Re: [RFC PATCH 3/5] drm/i915: register LVDS connector even if wecan't get a panel mode

[Seth Forshee]

On Fri, Aug 03, 2012 at 05:14:16PM +0100, Matthew Garrett wrote:
> On Fri, Aug 03, 2012 at 11:02:19AM -0500, Seth Forshee wrote:
> > Some Apple hybrid graphics machines do not have the LVDS panel connected
> > to the integrated GPU at boot and also do not supply a VBT. The LVDS
> > connector is not registered as a result, making it impossible to support
> > graphics switching.
> > 
> > This patch changes intel_lvds_init() to register the connector even if
> > we can't find any panel modes. This makes it necessary to always check
> > intel_lvds->fixed_mode before use, as it could now be NULL.
> 
> This one kind of sucks. I think adding a quirk for this situation would 
> be justifiable, rather than doing it for all devices.

This is one of the things I wasn't so sure about. There are various
checks in intel_lvds_init() that can cause it to bail out before we try
to get the EDID, and I don't fully understand all of them. If non-laptop
machines are expected to bail out before the EDID check then the
approach I've taken seems reasonable. Otherwise adding a quirk probably
is a good idea.

Seth

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