Hi Folks, I am trying to figure out where to submit a bug report for this issue. Let me just explain:
I have a dual monitor setup. Two identical Samsung 213Ts. One connects to laptop via displayport/DVI adapter, and another via VGA. The laptop is ThinkPad T440p. The video hardware is below. It is an Optimus setup (bumblebee works well, if that is relevant). ================================================== $ lspci -vnn | grep VGA 00:02.0 VGA compatible controller [0300]: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller [8086:0416] (rev 06) (prog-if 00 [VGA controller]) 02:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK208M [GeForce GT 730M] [10de:1290] (rev a1) (prog-if 00 [VGA controller]) ================================================== So here's the issue. Up until linux 4.3, I could connect both external monitors. Here is the output of uname and xrandr: ================================================== $ uname -a Linux nanook 4.3.0-1-amd64 #1 SMP Debian 4.3.3-7 (2016-01-19) x86_64 GNU/Linux $ xrandr Screen 0: minimum 8 x 8, current 2400 x 1600, maximum 32767 x 32767 eDP1 connected (normal left inverted right x axis y axis) 1600x900 60.01 + 1440x900 59.89 1368x768 60.00 1360x768 59.80 59.96 1152x864 60.00 1280x720 60.00 1024x768 60.00 1024x576 60.00 960x540 60.00 800x600 60.32 56.25 864x486 60.00 800x450 60.00 640x480 59.94 720x405 60.00 640x360 60.00 DP1 disconnected (normal left inverted right x axis y axis) DP2 disconnected (normal left inverted right x axis y axis) HDMI1 connected 1200x1600+0+0 left (normal left inverted right x axis y axis) 432mm x 324mm 1600x1200 59.98*+ 1280x1024 75.02 60.02 1152x864 75.00 1024x768 75.08 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 640x480 75.00 72.81 66.67 60.00 720x400 70.08 HDMI2 disconnected (normal left inverted right x axis y axis) VGA1 connected 1200x1600+1200+0 left (normal left inverted right x axis y axis) 432mm x 324mm 1600x1200 60.00*+ 1280x1024 75.02 60.02 1152x864 75.00 1024x768 75.08 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 640x480 75.00 72.81 66.67 60.00 720x400 70.08 VIRTUAL1 disconnected (normal left inverted right x axis y axis) ================================================== You can see one monitor hooked to HDMI1 and another to VGA1, plus the internal screen at eDP1. I can activate all three. But after upgrading to 4.4 or 4.5, I get the following (example for 4.5): ================================================== $ uname -a Linux nanook 4.5.0-2-amd64 #1 SMP Debian 4.5.5-1 (2016-05-29) x86_64 GNU/Linux $ xrandr Screen 0: minimum 8 x 8, current 1600 x 1600, maximum 32767 x 32767 eDP1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 309mm x 174mm 1600x900 60.01*+ 1440x900 59.89 1368x768 60.00 1360x768 59.80 59.96 1152x864 60.00 1280x720 60.00 1024x768 60.00 1024x576 60.00 960x540 60.00 800x600 60.32 56.25 864x486 60.00 800x450 60.00 640x480 59.94 720x405 60.00 640x360 60.00 DP1 disconnected (normal left inverted right x axis y axis) DP2 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) HDMI2 disconnected (normal left inverted right x axis y axis) VGA1 connected 1200x1600+0+0 left (normal left inverted right x axis y axis) 432mm x 324mm 1600x1200 60.00*+ 1280x1024 75.02 60.02 1152x864 75.00 1024x768 75.08 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 640x480 75.00 72.81 66.67 60.00 720x400 70.08 VIRTUAL1 disconnected (normal left inverted right x axis y axis) ================================================== Now it says that HDMI1 is disconnected. My stab-in-the-dark guess is that the HDMI1 connection is routed through one card (perhaps nvidia) and VGA1 through another (perhaps intel), and the driver/kernel could be confused about it. Would anyone know how to verify that? Or perhaps could you point me to the correct list/package? Thank you! And sorry if this is a duplicate. I have searched and searched but not found exactly the same issue. Collin
