Bug 15106

Summary: Intel 2.2.1 driver refuses to start up if no display is connected
Product: xorg Reporter: Simon Farnsworth <simon.farnsworth>
Component: Driver/intelAssignee: Gordon Jin <gordon.jin>
Status: RESOLVED DUPLICATE QA Contact: Xorg Project Team <xorg-team>
Severity: critical    
Priority: medium    
Version: unspecified   
Hardware: x86 (IA32)   
OS: Linux (All)   
i915 platform: i915 features:
Description Flags
X configuration
Log of failing startup none

Description Simon Farnsworth 2008-03-18 08:38:20 UTC
Created attachment 15251 [details]
X configuration

The 2.2.1 release of the Intel driver refuses to start if no screen is connected, despite a X configuration file telling it to go ahead anyway. The configuration used is attached.
Comment 1 Simon Farnsworth 2008-03-18 08:39:06 UTC
Created attachment 15252 [details]
Log of failing startup

And the logfile Xorg generates when we start up without a display
Comment 2 Simon Farnsworth 2008-03-18 09:55:56 UTC
Found the cause, and a workaround for us:

xf86ProbeOutputModes in Xorg's hw/xfree86/modes/xf86Crtc.c doesn't set up any modes for outputs that are definitely disconnected (output control function returns XF86OutputStatusDisconnected).

i830_crt_detect in the driver's src/i830_crt.c returns XF86OutputStatusDisconnected if one of the believed reliable detection methods returns false. The interaction between the two ensures that there are no modes available for a disconnected output.

In our situation, we can work around this by replacing XF86OutputStatusDisconnected with XF86OutputStatusUnknown in i830_crt_detect.
Comment 3 Michael Fu 2008-03-18 16:54:52 UTC
dup of bug# 14611...known behaviour for now. we will see if we would take this as a feature and will then reopen... thanks.

*** This bug has been marked as a duplicate of bug 14611 ***

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