vesa driver reports many modes, but only allows a few

[Ross Boylan]

On Tue, 2010-03-02 at 05:34 -0600, Pat Kane wrote:
> On Mon, Mar 1, 2010 at 2:35 PM, Ross Boylan <ross at biostat.ucsf.edu> wrote:
> > Do I need to create a complete xorg.conf?
> 
> 
> The command "Xorg -configure"  will create one for you.
Hooray!  With some hacking I got it working.  However, I want to report
that Xorg -configure generated a segfault, and I'd like to improve my
understanding of how configuration works.

First, I still don't understand how the defaults work. I thought xorg
was supposed to figure out default values for omitted sections.  Is it
really all or nothing, that is, no xorg.conf or one with all sections?

Second, Xorg -configure gave me a segfault.  Here's the terminal log:

X.Org X Server 1.7.5
Release Date: 2010-02-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.32.8-dsa-amd64 x86_64 Debian
Current Operating System: Linux squeeze00 2.6.32-trunk-amd64 #1 SMP Sun Jan 10 22:40:40 UTC 2010 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.32-trunk-amd64 root=UUID=5214601b-a9c6-496a-95cf-99962f6bb215 ro quiet
Build Date: 16 February 2010  10:23:38AM
xorg-server 2:1.7.5-1 (buildd at brahms.debian.org)
Current version of pixman: 0.16.4
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Tue Mar  2 10:06:16 2010
List of video drivers:
        mga
        siliconmotion
        sis
        chips
        s3
        savage
        trident
        voodoo
        ark
        apm
        neomagic
        nv
        vmware
        v4l
        rendition
        intel
        ati
        s3virge
        sisusb
        i128
        openchrome
        radeonhd
        mach64
        r128
        cirrus
        tdfx
        radeon
        tseng
        fbdev
        vesa
(++) Using config file: "/root/xorg.conf.new"
(EE) open /dev/fb0: No such file or directory

Backtrace:
0: Xorg (xorg_backtrace+0x28) [0x4a0b88]
1: Xorg (0x400000+0x64259) [0x464259]
2: /lib/libpthread.so.0 (0x7f8e67356000+0xe990) [0x7f8e67364990]
Segmentation fault at address (nil)

Fatal server error:
Caught signal 11 (Segmentation fault). Server aborting


Third, this did create an xorg.conf.new, but the only device section was
fbdev, not vesa.  It's unclear to me if any of the input device sections
had any effect, and the log shows a lot of failed attempts to set up
input devices.  Is that normal?  My expectation is that Xorg -config
figures out where things are and only puts in appropriate sections.
Maybe that's not possible because the naming of devices is unpredictable
across reboots?  For example, the generated file had
Section "InputDevice"
        Identifier  "Mouse0"
        Driver      "mouse"
        Option      "Protocol" "auto"
        Option      "Device" "/dev/input/mice"
        Option      "ZAxisMapping" "4 5 6 7"
EndSection

But I see no reference to /dev/input/mice in
Xorg.0.log.  /dev/input/mouse[012] are tried; all appear to fail with
(II) config/udev: Adding input device "ImExPS/2 Generic Explorer
Mouse" (/dev/input/mouse2)
(**) "ImExPS/2 Generic Explorer Mouse": always reports core events
(**) "ImExPS/2 Generic Explorer Mouse": Device: "/dev/input/mouse2"
(EE) ioctl EVIOCGNAME failed: Inappropriate ioctl for device
(II) UnloadModule: "evdev"

Thanks to Pat and Adam for their help.
Ross Boylan