https://bugs.freedesktop.org/show_bug.cgi?id=41366
Summary: HDMI on a Fusion board only comes up when LVDS is already enabled Product: DRI Version: XOrg CVS Platform: x86 (IA32) OS/Version: Linux (All) Status: NEW Severity: normal Priority: medium Component: DRM/Radeon AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: simon.farnsworth@onelan.co.uk
I'm running airlied's drm-fixes, git revision fdfc61594e6de21c23f955818ef78bcab9bafe40, and experiencing "interesting" times trying to get HDMI to work on a Fusion GPU (detected by X as [ 49.876] (--) RADEON(0): Chipset: "AMD Radeon HD 6310 Graphics" (ChipID = 0x9802)).
If I run: xrandr --output HDMI-0 --off xrandr --output LVDS --auto xrandr --output HDMI-0 --mode 1920x1200
the HDMI monitor comes up at 1920x1200
If I run: xrandr --output HDMI-0 --off xrandr --output LVDS --off xrandr --output HDMI-0 --mode 1920x1200
the HDMI monitor immediately enters DPMS Off state, and stays there.
I've confirmed with "grep . /sys/class/drm/card0-HDMI-A-1/*" that the kernel thinks the HDMI connector is switched on. The only difference I can see is that HDMI works when it gets CRTC 1, but not when it gets CRTC 0.
I have captured logs from the kernel with drm.debug=0x6 during the runs, in case that explains what's going on; I will attach them to this bug.