Bug 518251

I found other ways to freeze the machine. These seem different. The screens goes black and freezes there. There are 2 ways to produce this:
1- press the display switch hotkey without a monitor connected to the VGA output
2- execute "cat /proc/acpi/video/VGA/CRT/state" also without a monitor attached

In both case, if the machine boots with nomodeset, the problem goes mostly away. Without nomodeset the hang happens every time. With nomodeset it happens only sometimes (I think after playing with xrandr).

If found the culprit for this one. My temporary fix does not change the other type of freeze reported above.

So the problem is that both ways of producing the freeze execute the same acpi code which produces the freeze.
The code is :

Method (UPDD, 0, NotSerialized)
                {
                    If (LGreaterEqual (\_SB.OSTP (), 0x08))
                    {
                        Notify (\_SB.PCI0, 0x00)
                    }
                    Else
                    {
                        Notify (\_SB.PCI0.VGA, 0x00)

                    }

                    Sleep (0x02EE)
                    Store (0xFF, DVID)
                    Store (0x8E, CMD)
                    Store (Zero, SSMI)
                }
with the method \_SB.OSTP () returning 0 on my machine (It only checks for various windows version)
OperationRegion (PSIO, SystemIO, 0x0000FE00, 0x00000002)
OperationRegion (PSBF, SystemMemory, 0x3F6FBE92, 0x00000090)
     Field (\_SB.PSIO, ByteAcc, NoLock, Preserve)
            {
                SSMI,   8
            }
     Field (\_SB.PSBF, ByteAcc, NoLock, Preserve)
            {
                CMD,    8, 
                DVID,   32, 
                PSDT,   32
            }

The problem seems to be with the "Store (Zero, SSMI)" line. I commented it out and recompiled my DSDT. With the tuxonice kernel I was able to load it and my problem disappeared. I was able to do 1- and 2- above without any crash. In the gui, the output does change properly if a display is connected. But the output of "cat /proc/acpi/video/VGA/CRT/state" does not change anymore.

I'm confirming the same bug. Switching off external monitor causes the machine to lockup when KMS is active.

Since this bugzilla report was filed, there have been several major updates in various components of the Xorg system, which may have resolved this issue. Users who have experienced this problem are encouraged to upgrade their system to the latest version of their packages. For packages from updates-testing repository you can use command

yum upgrade --enablerepo='*-updates-testing'

Alternatively, you can also try to test whether this bug is reproducible with the upcoming Fedora 12 distribution by downloading LiveMedia of F12 Beta available at http://alt.fedoraproject.org/pub/alt/nightly-composes/ . By using that you get all the latest packages without need to install anything on your computer. For more information on using LiveMedia take a look at https://fedoraproject.org/wiki/FedoraLiveCD .

Please, if you experience this problem on the up-to-date system, let us now in the comment for this bug, or whether the upgraded system works for you.

If you won't be able to reply in one month, I will have to close this bug as INSUFFICIENT_DATA. Thank you.

[This is a bulk message for all open Fedora Rawhide Xorg-related bugs. I'm adding myself to the CC list for each bug, so I'll see any comments you make after this and do my best to make sure every issue gets proper attention.]

I tried Fedora 12 beta (live image on usb stick).
With that version, the problem in the original description is gone.

However the problem in the first comment is still present.
With some more checking I believe it is a kernel problem because:
1- starting linux in single mode (single kernel option)
2- cat /proc/acpi/video/VGA/CRT/state
 --> This produces a hang and the X server is not even running.
 This with kernel 2.6.31.1-56.fc12.i686
 Here the i915 modules is running

If I add the nomodeset kernel option in step 1-, the screen flickers but does not
hang the machine (the i915 module is still loaded but not used)

I checked the current Fedora 11 kernel and some older ones and they all behave in the same way.

P.S. I did not check that my ACPI fix works but I expect it to work.

I created a kernel bug #14556
  http://bugzilla.kernel.org/show_bug.cgi?id=14556

For the observations in comment 1 and 4

I can prevent the hotkey from hanging the machine by executing:
 echo 6 > /proc/acpi/video/VGA/DOS
(The value was 4 before that command)

This basically disables the hotkey (Fn-F8) on my system. It does not do anything anymore but at least it does not hang the machine either.

I can activate displays with xrandr and the display preference GUI.

Christian, in comment #4 you indicate that THIS bug is closed, is that correct? I'm sorry, but I have gotten confused with your comments in #5 and #6. 

-- 
Fedora Bugzappers volunteer triage team
https://fedoraproject.org/wiki/BugZappers

Sorry, it is my fault.
The problem in the original description of the bug report has been solved.

However, the additional problems I reported in comments 1 (part of 4 and 5,6)
are not solved. I should have opened another bug report for them.

I could still do that if you want me to.

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