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From: Daniel Vetter <daniel@ffwll.ch>
To: Florian Zumbiehl <florz@florz.de>
Cc: David Airlie <airlied@linux.ie>,
	intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: blank screen on boot with i915/DRM_FBDEV_EMULATION
Date: Tue, 29 Mar 2016 14:01:18 +0200	[thread overview]
Message-ID: <20160329120118.GW2510@phenom.ffwll.local> (raw)
In-Reply-To: <20160326112122.GF13320@florz.florz.de>

On Sat, Mar 26, 2016 at 12:21:23PM +0100, Florian Zumbiehl wrote:
> Hi,
> 
> I just compiled a new kernel version 4.4.5, replacing a previous 4.1.9 for
> my thinkpad x40, which replaced CONFIG_DRM_I915_FBDEV with
> CONFIG_DRM_FBDEV_EMULATION--now, when the i915 and fbcon modules get loaded
> during boot, the screen goes blank (with backlight still on), which didn't
> happen with the old kernel.
> 
> The funny thing is that starting an X server makes text reappear on the
> console!? (And the X server also works just fine, as far as I can tell so
> far ...)
> 
> i915 is loaded with modeset=1 (I remember I had some problem without it
> with some earlier kernels, I don't really remember the details anymore
> ...).
> 
> Any hints what to try? Any further information that could be useful?

FBDEV_EMULATION vs. I915_FBDEV is probably a read herring, more likely is
that for some odd reason the very first modeset fails. Once X has
resurrect the screen, can you then switch to fbcon? Also please check in
/sys/class/vtconsole whether the fbdev driver is loaded and bound (check
the name and bind files). And make sure there's that dmesg still says it
initialized the "inteldrmfb" driver.

If that all indicates fbcon is running properly, then it's time to bisect
what exactly broke the initial modeset for your system.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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  reply	other threads:[~2016-03-29 12:01 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-26 11:21 blank screen on boot with i915/DRM_FBDEV_EMULATION Florian Zumbiehl
2016-03-29 12:01 ` Daniel Vetter [this message]
2016-03-29 16:44   ` Florian Zumbiehl
2016-03-30  6:29     ` Daniel Vetter
2016-03-30 23:14       ` i951 ERRORs and WARN_ON()s (was: blank screen on boot with i915/DRM_FBDEV_EMULATION) Florian Zumbiehl
2016-04-12  1:23         ` Florian Zumbiehl
2016-04-27 10:03           ` Marius Vlad
2016-04-27 12:40             ` [Intel-gfx] " Florian Zumbiehl
2016-04-27 13:30               ` Jani Nikula
2016-04-29  2:27                 ` i915 ERRORs and WARN_ON()s Florian Zumbiehl
2016-04-29 10:30                   ` [Intel-gfx] " David Weinehall
2016-05-01  0:11                     ` Florian Zumbiehl
2016-05-01  9:37                       ` Daniel Vetter
2016-05-02  0:35                         ` Florian Zumbiehl

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