https://bugzilla.kernel.org/show_bug.cgi?id=60231

Summary: DisplayPort monitor not detected on PowerColor Radeon HD 4850 Product: Drivers Version: 2.5 Kernel Version: 3.10 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) AssignedTo: drivers_video-dri@kernel-bugs.osdl.org ReportedBy: prettyvanilla@lavabit.com Regression: No

Created an attachment (id=106381) --> (https://bugzilla.kernel.org/attachment.cgi?id=106381) dmesg output with dvi and displayport connected (drm.debug=0xE)

I have a dual-monitor setup via my PowerColor Radeon HD 4850 - one monitor is connected via DVI, the other (main) one via DisplayPort. While I was using fglrx that setup worked fine, with the radeon driver/module though only the dvi monitor is detected. DisplayPort is always reported as disconnected, no matter whether it is the only connected monitor at boot or is hotplugged later.

The monitors in question are a Samsung SyncMaster 970P via DVI and a Eizo FlexScan EV2333WH via DisplayPort. The Eizo does still work fine via DVI.

I'm currently running a 3.10 mainline kernel (+ radeon dpm patches) on Arch Linux. I remember trying this about 2 years ago I think, when it didn't work as well. Trying the 3.0 lts-kernel yields the same results, 3.10 mainline without dpm patches ditto.

I've attached the dmesg output with drm.debug=0xE set as kernel parameter.

I have found another bug report at launchpad that seems to describe the same issue: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1035556 Since that bug also happens on a PowerColor card, it seems likely to be a brand-/model-specific issue.