Bug#686939: linux-image-3.2.0-3-686-pae: fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver

[Steven Shiau <steven@nchc.org.tw>]

On 2012/9/19 上午 11:46, Ben Hutchings wrote:
> On Wed, 2012-09-19 at 10:09 +0800, Steven Shiau wrote:
> > On 2012/9/16 下午 01:13, Ben Hutchings wrote:
> > > On Fri, 2012-09-07 at 19:37 +0800, Steven Shiau wrote:
> > > > Source: linux
> > > > Version: 3.2.23-1
> > > > Severity: important
> > > >
> > > > Dear Maintainer,
> > > >
> > > > When using "nomodeset" and "vga=788" in the boot parameters, the machine hang at
> > > > "fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver"
> > > > on a machine with Intel VGA card.
> > > > This happens no matter it's 686-pae kernel, or i486 one.
> > > > Since the Intel VGA card in very common, please consider to make framebuffer work for KMS disabled.
> > >
> > > DRM drivers with KMS *are* framebuffer drivers.  I think you mean 'keep
> > > VGA console working'.
> > >
> > > > How to reproduce this:
> > > > 1. Create a Debian live based on Sid:
> > > >      http://live-build.debian.net/cgi-bin/live-build
> > > > 2. Burn the created iso on a CD, then boot it on a machine with Intel VGA card
> > > > 3. In the 1st boot menu of isolinux, press "Tab" key to modify the boot parameters. Just append "nomodeset vga=788", then press enter to continue boot
> > > > 4. The above error will shown, and it just hangs there.
> > >
> > > This is really weird because i915 just shouldn't register a console at
> > > all if you do that...  Ah, but xserver-video-xorg-intel still installs a
> > > configuration file which *overrides* nomodeset
> > > (/etc/modprobe.d/i915-kms.conf).  (There was a very good reason for
> > > doing that in squeeze, but I think it can be dropped now.)
> > >
> > > So you could avoid installing xserver-video-xorg-intel, or empty the
> > > configuration file.
> > >
> > > Still, the kernel should be able to switch without hanging (and normally
> > > does).  Does this *only* happen if you use 'nomodeset vga=788' or does
> > > it also happen if you use 'vga=788'?
> > It "only" happens when I use 'nomodeset vga=788'.
>
> Does /etc/modprobe.d/i915-kms.conf exist in the live system?
No. There is only a file /etc/modprobe.d/fbdev-blacklist.conf in the dir 
/etc/modprobe.d/.
> > However, when using "vga=788", actually it won't work since the console
> > screen is not in the 800x600 text mode. It's in KMS mode I believe.
>
> Yes, by default i915 will load and set the screen mode immediately.
Got it. Sure.
Thanks.

Steven.
> Ben.

--
Steven Shiau <steven _at_ nchc org tw> <steven _at_ stevenshiau org>
National Center for High-performance Computing, Taiwan.
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