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

From: Daniel Vetter <daniel@ffwll.ch>
To: Matthew Garrett <mjg59@srcf.ucam.org>,
	dri-devel@lists.freedesktop.org,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	David Airlie <airlied@linux.ie>,
	linux-kernel@vger.kernel.org, Andreas Heider <andreas@meetr.de>
Subject: Re: [RFC PATCH 3/5] drm/i915: register LVDS connector even if we can't get a panel mode
Date: Sun, 5 Aug 2012 23:14:12 +0200	[thread overview]
Message-ID: <20120805211412.GG12232@phenom.ffwll.local> (raw)
In-Reply-To: <20120804165727.GA4980@thinkpad-t410>

On Sat, Aug 04, 2012 at 11:57:27AM -0500, Seth Forshee wrote:
> On Fri, Aug 03, 2012 at 05:27:02PM +0100, Matthew Garrett wrote:
> > On Fri, Aug 03, 2012 at 11:24:51AM -0500, Seth Forshee wrote:
> > 
> > > 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.
> > 
> > I know we've previously had problems with machines with phantom LVDS 
> > hardware, but I'm not sure what the current state of affairs is.
> 
> It turns out that the framebuffer console issue is due to not having a
> mode when initializing LVDS. As a result 1024x768 is getting used for
> the framebuffer.
> 
> So quirking is going to fix this situation. In fact, with the changes
> below switcheroo seems to work perfectly, without any of these patches
> at all.

I like this approach more - the only other solution I see is to ask the
currently active driver (i.e. radeon) at bootime for the right mode. Which
sounds much more hellish and fragile ...
-Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48