BulletProofX

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See also:
 * [[Xorg7.3Integration]] - Upgrading to Xorg 7.3 and adopting xorg.conf autodetection feature
 * [[DisplayConfigGTK]] - Adopting GUI Xorg configuration tool
 * UnifiedLoginUnlock - Improving login screen consistency and reduce user confusion
 * XorgCtrlAltBackspace - Disabling ctrl-alt-backspace to reduce user confusion
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This specification describes a new failsafe mode that will be used if X
fails to start up. It will be in a reduced (VESA or VGA) graphics
environment, 800x600/256, running a single application
(gtk-displayconfig) for configuring the graphics devices.
This specification describes a new failsafe mode that will be used if X fails to start up. It will be in a reduced (VESA 800x600/256 or VGA 640x480/16) graphics environment running a single application (displayconfig-gtk) for configuring the graphics devices.

The goal of this specification is to eliminate the need for users to need to run apt-get reconfigure on the commandline. That approach is confusing and too technical for many users, so moving away from that will solve a key pain point for users.
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# TODO
This section should include a paragraph describing the end-user impact of this change. It is meant to be included in the release notes of the first release in which it is implemented.

It is mandatory.
This is a failsafe mode for X that will launch if the /etc/X11/xorg.conf file does not result in a working graphical environment due to Xorg failing to start. It can also be invoked manually by specifying 'xforcevesa' via grub's kernel cmdline option, by setting the XORG_FAILSAFE_MODE environment variable to a non-empty string, or by selecting the Failsafe option from the Greeter.
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Xorg sometimes fails to launch for some users, typically due to failure
to detect hardware properly during installation or when the user has
changed monitors or graphics cards.
Xorg sometimes fails to launch for some users, typically due to failure to detect hardware properly during installation or when the user has changed monitors or graphics cards.
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Currently ubuntu support has the user re-run apt-get reconfigure, but
this is confusing and too technical for many users, who complain about
this. So the sooner we can move away from requiring that, the better.
Currently Ubuntu support has the user re-run dpkg-reconfigure, but this is confusing and too technical for many users, who complain about this. So the sooner we can move away from requiring that, the better.
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 * Bob changes his monitor for an older one because his monitor broke. Xorg fails to launch because the 'new' (the older one) monitor fails to work with the frequency configured. Bob want to use the older monitor while his monitor is being repaired.
 * Cynthia installs for the first time and everything is properly detected except color depth is too high, thus consuming too much memory and preventing X from starting
 * Dustin upgrades his graphics adapter and Xorg fails because of an existing configuration for the previous graphics adapter.
 * Bob changes his monitor for an older one because his monitor broke. Xorg fails to launch because the monitor fails to work with the frequency configured. Bob want to use the older monitor while his monitor is being repaired.
 * Cynthia installs for the first time and everything is properly detected except that the color depth is too high, thus consuming too much memory and preventing X from starting.
 * Dustin upgrades his graphics adapter and Xorg fails because of the existing configuration for the previous graphics adapter.
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 * That most failed-to-detect scenarios involve hardware that supports VESA or VGA modes
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The failsafe mode will be initiated by gdm if it fails to start X, or if
an environment variable or commandline option is passed in. This should
also permit forcing vesa mode via the boot parameters.
=== GDM Failsafe Server ===
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Failsafe mode runs with administrative permissions since it will likely
need to alter the user's xorg.conf. Because of this, the user will need
to authenticate. However, care must be taken to ensure the user notices
that this is an abnormal situation; the authentication request must not
be confused with the standard login screen.
The failsafe mode will be initiated by gdm if it fails to start X, or if an environment variable or command-line option is passed in. This should also permit forcing vesa mode via the boot parameters.
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In this mode, the current xorg.conf will be ignored; instead a VESA
800x600/256 configuration will be used. In some (rare) cases, hardware
may not support VESA, in which case a VGA/16 mode will be the fallback.
These cases will be tracked by means of a blacklist file.
Failsafe mode runs with administrative permissions since it will likely need to alter the user's xorg.conf. Because of this, the user will need to authenticate. However, care must be taken to ensure the user notices that this is an abnormal situation; the authentication request must not be confused with the standard login screen.
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When launched into failsafe mode, a single application will be presented
to the user: gtk-displayconfig. A window manager will be needed since
gtk-displayconfig has some popup dialogs, but even a simple window
manager should suffice. This application will provide several
functionalities:
In this mode, the current xorg.conf will be ignored; instead a VESA 800x600/256 configuration will be used. In some (rare) cases, hardware may not support VESA, in which case a VGA 640x480/16 mode will be the fallback, or framebuffer if that won't work either. These cases will be tracked by means of a blacklist file.
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 * Help screen When launched into failsafe mode, a single application will be presented to the user: gtk-displayconfig. A window manager will be needed since gtk-displayconfig has some popup dialogs, but even a simple window manager should suffice. This application will provide several functionalities:

 * Welcome screen
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   * i18n / translatable
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=== KDM Failsafe Server ===

KDM currently does not support a failsafe server as GDM does, so support for this capability on KDM-based distros will be deferred until this has been implemented. Assuming a design similar to GDM is adopted, the above design can be used here as well.

=== Live CD ===

The above failsafe mode won't be used on the Live CD for Gutsy. If there is an Xorg startup failure when running the live-cd, then it should directly go to vesa mode without requiring any configuration step.
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    AlwaysRestartServer=true # Maybe, only if GDM isn't forcing a complete X restart
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    * If the previous X session crashed     * If the previous X session crashed (i.e., gdm never got the signal back from the X server that it started up).
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    * Use EDID + lspci as key to lookup     * Use EDID + PCI IDs as key to lookup (Can get PCI IDs from discover)
    * If the display does not give EDID info, then use VGA 640x480/16 mode
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 6. Start up the failsafe X session
 7. Launch displayconfig-gtk application
 8. Display a welcome screen explaining why the user is in this mode and
    what they have to do to solve the issue encountered.
 9. Provide a button that allows user to skip configuration and just
    launch Xorg with the VESA (or VGA) mode.
 6. Start up the failsafe X session using their regular user account
 7. Launch displayconfig-gtk (gnome) or displayconfig (kde) application, under gksu
    * Initiate it using an option to let it know we're using it in failsafe mode
    * Make sure to pass along environment variables for hardware preferences
    * Provide welcome screen text explaining why the user is in this mode and what they have to do to solve the issue encountered.
    * Provide a button that allows user to skip configuration and just launch Xorg with the VESA (or VGA) mode.
    * Provide checkbox "Never prompt for reconfiguring"
 8. If user chooses to skip configuration, launch X using the temporary failsafe xorg.conf, one time
 9. If the user selects the "Never prompt for reconfiguring" option, then set the following in /etc/gdm/gdm.conf:
    FailsafeXServer=
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=== Acceptance Testing ===
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     * Deliberately misconfigured X (mismatched kernel/X drivers, bad resolutions, wrong refresh rates, invalid options, etc.)
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 5. Verify mouse and keyboard work properly
 6. Verify GUI config tool is running
 5. Verify mouse and keyboard work properly and that keyboard layout matches that listed in /etc/X11/xorg.conf
 6. Verify displayconfig-gtk is running
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     - Especially check restricted drivers, including fglrx and nvidia
     - Also test when specifying hardware selection preferences using environment variables
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 13. When writing out the xorg.conf, it must preserve any data that existed beforehand. Ideally, it must preserve formatting of this data as well, so diffs will show only meaningful lines changed.
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Rerun the test with different language settings, selecting different
resolutions, and selecting incorrect driver/hardware combinations.
=== Fault Handling Testing ===
Also test the following situations to make sure they're handled appropriately:
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== Outstanding Issues ==  * Different language settings
 * Systems with primary and secondary video cards, with display connected to secondary
 * System booted with monitor turned off initially
 * Systems with mis-detected color ranges, which can prevent xorg from loading
 * Test R500 / Radeon X1300 - X1950 hardware - this has had problems with vesa mode in the past, but a patch exists to fix it. Since this is a common kind of hardware, especially for laptops, we need to ensure this patch is included in Gutsy.
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 * Which window manager to use for the failsafe mode? === Usability Testing ===
 * Check if having to authenticate during failsafe adds too much complexity/confusion for users
 * Check if users with really thrashed up systems (glx drivers, wrong/mismatched restricted drivers in kernel, etc.) are able to get into failsafe mode gracefully and clean up their system satisfactorily.
 * Check the time required by a novice user to hook up a non-EDID projector, boot into failsafe mode, reconfigure, and launch X with an acceptable resolution. It should not require more than 5-10 min max.
 * Check that appropriate error messages given if user selects incorrect driver/hardware/resolution combinations
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 * If the user is required to authenticate to use the configuration tool, will this cause added complexity/confusion for the user?
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 * When writing out xorg.conf, it must preserve any data that existed beforehand. Ideally, it must preserve formatting of this data as well, so diffs will show only meaningful lines changed. == Deferred Capabilities ==
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 * kdm does not have a gdm-style trigger for going into failsafe mode, so such a capability would need to be added.

 * Does xrandr have a mechanism for exporting the config, so we can apply changes immediately?
     * May need to write some tools to run xrandr to read this
     * There isn't a tool for writing the changes, but that should be a small tool to make
 * ''What about Kubuntu? Since displayconfig-gtk is a port from KDE, I figure it shouldn't be too hard to support that too. --ColinWatson''
  * A pre-requisite to this is to have a gdm-style trigger for going into failsafe mode. I checked with the KDM guys at UDS, and they confirmed it lacks this ability, and it didn't sound likely that it would be added in time for Gutsy, so we may need to defer supporting this for now.
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  * ''Do we think this is widespread? Is it worth specifying that we need to add this to gtk-displayconfig? --ColinWatson''
   * It's probably not common enough to worry about, but when configuring dual-head with the nvidia binary driver on a 64-bit system, I did have to fiddle with some Options. So I think it's safe to defer this for now, as it doesn't regress us from how things work currently, but it might be a nice-to-have for the future.
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 * If GDM does not force a complete X restart, the following may need to be added to /etc/gdm/gdm.conf: == Suggestions ==
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   AlwaysRestartServer=true  * What about monitors that lie about their capabilities? in such cases the user will just be presented with a 'signal out of range' error, and the X server and GDM are none the wiser. Is there a fallback scenario for that? Since the user cannot see what is going on, there is not a lot they can do, and is highly likely to just reset the machine by power-button or reset button. Perhaps we should detect such an event and present the user with the failsafe X server when a user has not logged on after a reboot and the filesystem has not been unmounted cleanly? I know this seems pretty arbitrary, and it probably is. This is just a brainwave. --HeinPietervanbraam
  * One option could be along the lines of what the Windows bootloader does when it's not able to bring up the GUI:
   1. There would be a certain file, let's call it /var/log/lastX.gdmstartup.
   1. When GDM starts, before trying to bring up X, it would remove the file.
   1. Later, at the first UI action in GDM, the file would be touched.
   1. This would allow a boot-time script to check for the existence of such file. If it does not exist, either X was not correctly displayed (bad sync went undetected, etc) or the computer just rebooted without any login (i.e. power loss). The script would then bring up a curses-based menu offering to enter GUI failsafe mode, console mode, or ignore the error and enter the normal GUI. --Habbit
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== BoF agenda and discussion ==

Bulletproof-X

Fallback: try first Vesa, then VGA 640x480x16, then Framebuffer. if fallback mode is activated, launch displayconfig-gtk.

<sebas> Keith Packard said that the 'safest mode' is 800x600/16 since that's what's used by Windows default (and thus tested for really every graphics chip.

fallback to vesa - failsafe. Supposed to work 100%, but some hardware. Or fallback to 256 or 16 vga if that doesn't work. Create blacklist for cards that vesa fails on (like R500). May have to provide a grub boot option.
An X crashing should revert back to a known-good Blacklist not a terribly good idea, since it isn't future-proof at all. True but the vesa failure is quite likely a very rare issue, and a whitelist would be even worse. VESA failure is seemingly a very big thing w/feisty since Radeon X1300 - X1950 series is so common nowadays on laptops etc. Sounds like a good thing to blacklist.
<tepsipakki> r5xx vesa failure is a bug with a fix. There should be no need for a white/blacklist.

Fallback Use Cases:
 * Bob changes his monitor for an older one because his monitor broke. Xorg fails to launch because the 'new' (the older one) monitor fails to work with the frequency configured. Bob want to use the older monitor while his monitor is being repaired.
 * Ann changes her VGA for a new one. Xorg fails to start.
 * John upgrades his graphics adapter and Xorg fails because of an existing configuration for the previous graphics adapter.
 * Amy installs for the first time and everything is properly detected except color depth is too high, thus consuming too much memory and preventing X from starting

Use Cases for problem areas:
 * Install-time - x not detecting correctly
 * Update-time - x breaking during updates

Currently ubuntu support has the user re-run apt-get reconfigure, but
this is confusing and too technical for many users, who complain about
this. So the sooner we can move away from requiring that, the better.

The debconfage is going away. Current xorg in debian-unstable has removed the need for Modules and Fonts, rest is on the horizon.

We will need to replace the current install infrastructure with new one using the xrandr and pci-id list approach... We may need to continue with the current xresprobe/ddcprobe stuff for ISA or older systems, but for most known audience we can expect the xrandr approach to be workable.

Marc Tardif is working on some things to work around these problems, so if gutsy will be fixing this in the coming few months it could save him some time. We probably need to get synced up.

Guadalinux does extensive testing of their ubuntu-based installs, so if we can tie our efforts in with their schedule they could test the rollout of it. Already have >400,000 users in 1100 schools. They're having small updates almost once a day. They do testing from June-September (May to October). HW varies - i965, i945, i815 typically. Rage and nvidia on a few laptops. Currently they have few problems with monitor resolution detection (xserver-xorg-video-intel 2.0 did not make it to 7.04, but 1.9.94 is in universe). Since they have a controlled environment, we probably should have few issues and should be pretty easy to validate.

A major pre-requisite for this is to get the driver xrandr support in all the drivers. radeon support was added last night; nouveau we can expect to have xrandr before too long.
dnusinow said on #debian-x last night:
02:38 < gravity> I need to add one more feature for my module defaults patch upstream, and I also need to figure out exactly how to get rid of discover
02:39 < gravity> I don't really understand how the server figures out which driver to load when there's no xorg.conf yet
02:43 < gravity> The other thing that the xserver postinst depends on is xresprobe. I haven't decided if I want to get rid of it yet.
02:44 < gravity> randr1.2 depends on having DDC info available. If the monitor doesn't send that, then xresprobe could tell the postinst that the DDC info is missing so that the postinst can write some default values to xorg.conf
02:45 < gravity> On the other hand, the server should probably just fill in some default values itself. I don't know if it does that yet.
02:45 < gravity> If so, we can dump xresprobe as well.
02:45 < gravity> At which point we just wait for all the drivers to get randr1.2 support and for input hotplugging to land. Then our job becomes significantly easier
02:48 < bgoglin> just wait a couple years then :)
02:51 < gravity> hehe
02:51 < gravity> Realistically, it's already here. Just don't give people a choice in the debconfage, let the server just look in /dev/input/mice, and load kbd and mouse, and we cover 99% of the use cases
02:52 < gravity> Anyone who wants something weirder can just write their own conf :-)
02:52 < bgoglin> :)

Technical design for bulletproof-x

xforcevesa should stay, but we should implement this at a closer level, perhaps with an x startup script that checks your hardware against the blacklist, and then switch to vesa mode. Does a pcid check.

A case for this would be if the user upgrades their graphics card, and wants it to work without editing xorg.conf, etc. Getting rid of Device-section is the next goal for debian. If the device in the old conf doesn't work, fallback using what the server would use automatically.

In some cases the color range is mis-detected, preventing xorg to load. Perhaps here we need to detect the amount of video ram available to verify the color depth. Log files report this specific error and may be used to trigger fallback.

Probably the fewer fallback modes, the better, even if the fallback modes are less capable than they could be, since then to support the user there'll just be one state they will be starting from, so it'll be simpler to walk them through it, and since they (ideally) won't be in that mode normally.

In fallback mode, it would run with a single application (displayconfig-gtk). We'll need a simple window manager since it has a few popup dialogs for selecting drivers, etc.

During fallback mode, should we have a user login or just automatically log them in? Probably have them end up in their regular login, then they can sudo to run setup programs. This should also provide a small subset of the tools - displayconfig-gtk, restricted driver manager?, (probably not synaptic or terminals...) Button to override and go to login anyway, but also hooks to force / help hardware config scenarios where automation is required.

Also will need to have an override way to force it into or out of this mode (maybe a commandline option or something?) for validation testing. Or instead have it simply log a failure but skip going into the mode.

Will also need a help file to explain being in fallback mode + how to get out. Ideally, this should be i18nable as well. We'll need to doublecheck that displayconfig-gtk is able to include this.

How about a mechanism to allow getting into a failsafe mode with a working Firefox webbrowser so they can search the net to find out how to fix the problem?

VESA 800x600x256 is required by the Window logo problem. So we may as well accept that as the default for our failsafe mode. For monitors without EDID, maybe we'll need to go down to 640x480.

Also include option "this is good enough" so user can just stick with the generic vesa mode without having to continually go through the failsafe mode first.

What about on the live CD? It allows for selecting to go to a failsafe mode. In a live-cd failure it should go directly to the failsafe mode without requiring any configuration step.

We might want to just extract the data from 'discover' rather than carry discover as a full dependency if its pci-id list is the only thing needed.

LiveCD: if the user has to configure anything on the livecd, then we've failed. So if X fails, go straight to the fallback.

VESA 800x600x256 is guaranteed by MS Windows logo requirements.

What if the user has thrashed up their system by messing up e.g. glx drivers, have a wrong nvidia driver in the kernel, or etc. Will this vesa mode be able to be loaded.
 * There is a tarball available but no details how to do stuff at http://people.ubuntu.com/~bryce/BulletProofX/

Please check the status of this specification in Launchpad before editing it. If it is Approved, contact the Assignee or another knowledgeable person before making changes.

  • Launchpad Entry: bullet-proof-x

  • Packages affected: displayconfig-gtk, gdm, Xorg

See also:

Summary

This specification describes a new failsafe mode that will be used if X fails to start up. It will be in a reduced (VESA 800x600/256 or VGA 640x480/16) graphics environment running a single application (displayconfig-gtk) for configuring the graphics devices.

The goal of this specification is to eliminate the need for users to need to run apt-get reconfigure on the commandline. That approach is confusing and too technical for many users, so moving away from that will solve a key pain point for users.

Release Note

This is a failsafe mode for X that will launch if the /etc/X11/xorg.conf file does not result in a working graphical environment due to Xorg failing to start. It can also be invoked manually by specifying 'xforcevesa' via grub's kernel cmdline option, by setting the XORG_FAILSAFE_MODE environment variable to a non-empty string, or by selecting the Failsafe option from the Greeter.

Rationale

Xorg sometimes fails to launch for some users, typically due to failure to detect hardware properly during installation or when the user has changed monitors or graphics cards.

Currently Ubuntu support has the user re-run dpkg-reconfigure, but this is confusing and too technical for many users, who complain about this. So the sooner we can move away from requiring that, the better.

Use Cases

  • Annette occasionally gives presentations at work on an old projector, but X fails to start when the projector is connected to her Ubuntu laptop, leaving her at the command prompt. Because of this, she has to move her presentation to someone else's non-Ubuntu laptop, but she'd rather be able to use her own.
  • Bob changes his monitor for an older one because his monitor broke. Xorg fails to launch because the monitor fails to work with the frequency configured. Bob want to use the older monitor while his monitor is being repaired.
  • Cynthia installs for the first time and everything is properly detected except that the color depth is too high, thus consuming too much memory and preventing X from starting.
  • Dustin upgrades his graphics adapter and Xorg fails because of the existing configuration for the previous graphics adapter.

Assumptions

  • That most failed-to-detect scenarios involve hardware that supports VESA or VGA modes

Design

GDM Failsafe Server

The failsafe mode will be initiated by gdm if it fails to start X, or if an environment variable or command-line option is passed in. This should also permit forcing vesa mode via the boot parameters.

Failsafe mode runs with administrative permissions since it will likely need to alter the user's xorg.conf. Because of this, the user will need to authenticate. However, care must be taken to ensure the user notices that this is an abnormal situation; the authentication request must not be confused with the standard login screen.

In this mode, the current xorg.conf will be ignored; instead a VESA 800x600/256 configuration will be used. In some (rare) cases, hardware may not support VESA, in which case a VGA 640x480/16 mode will be the fallback, or framebuffer if that won't work either. These cases will be tracked by means of a blacklist file.

When launched into failsafe mode, a single application will be presented to the user: gtk-displayconfig. A window manager will be needed since gtk-displayconfig has some popup dialogs, but even a simple window manager should suffice. This application will provide several functionalities:

  • Welcome screen
    • Explain why we're in failsafe mode
    • Synopsis of how to use gtk-displayconfig to get out of this mode
    • Where to get further information
    • i18n / translatable
  • Skip configuration (Just run X in reduced (VESA) mode)
    • [ ] Never prompt for reconfiguring
  • Specify graphics card, monitor, and driver(s)
  • Select resolution and refresh rate
  • Write out xorg.conf with new changes
    • Use temporarily (just this session)
    • Use as the permanent default

KDM Failsafe Server

KDM currently does not support a failsafe server as GDM does, so support for this capability on KDM-based distros will be deferred until this has been implemented. Assuming a design similar to GDM is adopted, the above design can be used here as well.

Live CD

The above failsafe mode won't be used on the Live CD for Gutsy. If there is an Xorg startup failure when running the live-cd, then it should directly go to vesa mode without requiring any configuration step.

Implementation

  1. Create shell script for gdm to run if the X server crashes
    • /etc/gdm/failsafeXServer
  2. In /etc/gdm/gdm.conf indicate this failsafe server
    • FailsafeXServer=/etc/gdm/failsafeXServer

      AlwaysRestartServer=true # Maybe, only if GDM isn't forcing a complete X restart

  3. Also provide access to the failsafe session via the greeter
  4. Configure gdm to also invoke the FailsafeXServer script in any of the following cases:
    • If the previous X session crashed (i.e., gdm never got the signal back from the X server that it started up).
    • Environment variable XORG_FAILSAFE_MODE is defined
    • /proc/cmdline contains option xforcevesa
    • If the user selects the Failsafe option from the chooser
  5. When failsafe mode is activated, check the blacklist for systems we know do not support VESA 800x600/256
    • Use EDID + PCI IDs as key to lookup (Can get PCI IDs from discover)
    • If the display does not give EDID info, then use VGA 640x480/16 mode
    • If a matching entry is found, then use VGA 640x480/16 mode
  6. Start up the failsafe X session using their regular user account
  7. Launch displayconfig-gtk (gnome) or displayconfig (kde) application, under gksu
    • Initiate it using an option to let it know we're using it in failsafe mode
    • Make sure to pass along environment variables for hardware preferences
    • Provide welcome screen text explaining why the user is in this mode and what they have to do to solve the issue encountered.
    • Provide a button that allows user to skip configuration and just launch Xorg with the VESA (or VGA) mode.
    • Provide checkbox "Never prompt for reconfiguring"
  8. If user chooses to skip configuration, launch X using the temporary failsafe xorg.conf, one time
  9. If the user selects the "Never prompt for reconfiguring" option, then set the following in /etc/gdm/gdm.conf:
    • FailsafeXServer=

Test/Demo Plan

Acceptance Testing

  1. Install Failsafe X package for testing
  2. Reboot and use each available mechanism to force failsafe mode
    • Set environment variable
    • Option specified in /proc/cmdline
    • Failsafe mode selected from chooser
    • Deliberately misconfigured X (mismatched kernel/X drivers, bad resolutions, wrong refresh rates, invalid options, etc.)
  3. Check that the /etc/X11/xorg.conf file is not being used
  4. Verify screen comes up as 800x600/256
  5. Verify mouse and keyboard work properly and that keyboard layout matches that listed in /etc/X11/xorg.conf
  6. Verify displayconfig-gtk is running
  7. Check that help text and interface is internationalized appropriately
  8. Check if displayconfig-gtk identifies the hardware correctly and selects the correct driver
    • - Especially check restricted drivers, including fglrx and nvidia - Also test when specifying hardware selection preferences using environment variables
  9. Verify the GUI provides the correct listing of resolutions and refresh rates for the selected configuration
  10. Verify that the system can drop to lower resolutions such as 640x480.
  11. Verify that the system can go to the maximum resolution supported by the hardware
  12. Verify that the xorg.conf is written with the options selected through the GUI
  13. When writing out the xorg.conf, it must preserve any data that existed beforehand. Ideally, it must preserve formatting of this data as well, so diffs will show only meaningful lines changed.

Fault Handling Testing

Also test the following situations to make sure they're handled appropriately:

  • Different language settings
  • Systems with primary and secondary video cards, with display connected to secondary
  • System booted with monitor turned off initially
  • Systems with mis-detected color ranges, which can prevent xorg from loading
  • Test R500 / Radeon X1300 - X1950 hardware - this has had problems with vesa mode in the past, but a patch exists to fix it. Since this is a common kind of hardware, especially for laptops, we need to ensure this patch is included in Gutsy.

Usability Testing

  • Check if having to authenticate during failsafe adds too much complexity/confusion for users
  • Check if users with really thrashed up systems (glx drivers, wrong/mismatched restricted drivers in kernel, etc.) are able to get into failsafe mode gracefully and clean up their system satisfactorily.
  • Check the time required by a novice user to hook up a non-EDID projector, boot into failsafe mode, reconfigure, and launch X with an acceptable resolution. It should not require more than 5-10 min max.
  • Check that appropriate error messages given if user selects incorrect driver/hardware/resolution combinations

Deferred Capabilities

  • What about Kubuntu? Since displayconfig-gtk is a port from KDE, I figure it shouldn't be too hard to support that too. --ColinWatson

    • A pre-requisite to this is to have a gdm-style trigger for going into failsafe mode. I checked with the KDM guys at UDS, and they confirmed it lacks this ability, and it didn't sound likely that it would be added in time for Gutsy, so we may need to defer supporting this for now.
  • If resolution of the failed X configuration requires specification of xorg.conf Options, the user will still need to manually add these, because gtk-displayconfig does not currently provide a list of available Options to select from.
    • Do we think this is widespread? Is it worth specifying that we need to add this to gtk-displayconfig? --ColinWatson

      • It's probably not common enough to worry about, but when configuring dual-head with the nvidia binary driver on a 64-bit system, I did have to fiddle with some Options. So I think it's safe to defer this for now, as it doesn't regress us from how things work currently, but it might be a nice-to-have for the future.

Suggestions

  • What about monitors that lie about their capabilities? in such cases the user will just be presented with a 'signal out of range' error, and the X server and GDM are none the wiser. Is there a fallback scenario for that? Since the user cannot see what is going on, there is not a lot they can do, and is highly likely to just reset the machine by power-button or reset button. Perhaps we should detect such an event and present the user with the failsafe X server when a user has not logged on after a reboot and the filesystem has not been unmounted cleanly? I know this seems pretty arbitrary, and it probably is. This is just a brainwave. --HeinPietervanbraam

    • One option could be along the lines of what the Windows bootloader does when it's not able to bring up the GUI:
      1. There would be a certain file, let's call it /var/log/lastX.gdmstartup.
      2. When GDM starts, before trying to bring up X, it would remove the file.
      3. Later, at the first UI action in GDM, the file would be touched.
      4. This would allow a boot-time script to check for the existence of such file. If it does not exist, either X was not correctly displayed (bad sync went undetected, etc) or the computer just rebooted without any login (i.e. power loss). The script would then bring up a curses-based menu offering to enter GUI failsafe mode, console mode, or ignore the error and enter the normal GUI. --Habbit
  • There is a tarball available but no details how to do stuff at http://people.ubuntu.com/~bryce/BulletProofX/


CategorySpec

BulletProofX (last edited 2008-08-06 16:35:43 by localhost)