[Intel-gfx] [PATCH] drm/i915: Ignore LVDS presence in VBT flag if the LVDS is enabled by BIOS

[Daniel Vetter]

On Mon, Jun 22, 2015 at 02:17:16PM +0100, Damien Lespiau wrote:
> On Fri, Jun 19, 2015 at 01:57:43PM +0100, Chris Wilson wrote:
> > On older gen, pre-Ironlake, parts there is no hardwired pin to report
> > the presence of an LVDS panel. Instead, we have to rely on the VBT to
> > declare whether the machine has a panel or not. Though notoriously
> > unreliable, so far we have erred on the side of false-positives and have
> > required a list of machines which end up falsely reporting a panel as
> > present. However, we now have reports of false-negatives, machines with
> > an LVDS that are being ignored due to the VBT not declaring the panel.
> > This patch ignores the VBT setting if the BIOS has already enabled the
> > LVDS panel (and on Ironlake+ we also have the hardware presence pin).
> > 
> > It fixes the Samsung NP680Z5E-X01FR in the bug report, but is likely to
> > result in more false-positives, and since we rely on the BIOS to enable
> > the panel, there are likely different circumstances where the BIOS will
> > not enable that panel (and so we may see the same machine with and
> > without a panel all on the whim of the BIOS).
> > 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90979
> > Reported-and-tested-by: lysxia at gmail.com
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> 
> Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>

On popular request (Jani) queued for -next for a bit of soaking time,
thanks for the patch.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch