Bug 107650 - Invalid three-monitor setup configured for LVDS/DP/HDMI
Summary: Invalid three-monitor setup configured for LVDS/DP/HDMI
Status: RESOLVED MOVED
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/modesetting (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-08-21 17:14 UTC by Simon Richter
Modified: 2018-12-13 18:12 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Attachments
X log, three-monitor setup, DP port in HDMI mode (works) (45.20 KB, text/plain)
2018-08-21 17:14 UTC, Simon Richter
no flags Details
X log, three-monitor setup, DP port in DP mode (fails) (50.71 KB, text/plain)
2018-08-21 17:14 UTC, Simon Richter
no flags Details

Description Simon Richter 2018-08-21 17:14:22 UTC
Created attachment 141223 [details]
X log, three-monitor setup, DP port in HDMI mode (works)

When two external monitors supporting the same timings are connected, the driver attempts to reuse a CRTC, however this fails if one is connected via DP and the other via HDMI or DVI, as the DP link requires a different PLL setup.

xrandr handles this restriction, reporting an error from the CRTC setup (the virtual CRTC 2 just reports failure), but on startup, this check is not performed properly, and the X server starts up with two usable displays and one confused monitor that will neither go to powersave nor show a picture.
Comment 1 Simon Richter 2018-08-21 17:14:57 UTC
Created attachment 141224 [details]
X log, three-monitor setup, DP port in DP mode (fails)
Comment 2 GitLab Migration User 2018-12-13 18:12:35 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/xorg/xserver/issues/65.


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