Hi.
With Linux 4.4 external HDMI-attached monitor in not discovered by i915 driver. Here is boot log related to drm and i915 for Linux 4.4/4.4.1 kernel:
=== kernel: [drm] Initialized drm 1.1.0 20060810 kernel: [drm] Memory usable by graphics device = 2048M kernel: [drm] Replacing VGA console driver kernel: [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). kernel: [drm] Driver supports precise vblank timestamp query. kernel: [drm] Initialized i915 1.6.0 20151010 for 0000:00:02.0 on minor 0 kernel: i915 0000:00:02.0: No connectors reported connected with modes kernel: [drm] Cannot find any crtc or sizes - going 1024x768 kernel: i915 0000:00:02.0: fb0: inteldrmfb frame buffer device ===
i915 is unable to find any connectors. Reattaching HDMI cable does not help. Note, we are talking about in-kernel i915 drm with no X involved (launching X does not change anything, though).
Linux 4.3 worked OK. Here is boot log for 4.3 kernel:
=== kernel: [drm] Initialized drm 1.1.0 20060810 kernel: [drm] Memory usable by graphics device = 2048M kernel: [drm] Replacing VGA console driver kernel: [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). kernel: [drm] Driver supports precise vblank timestamp query. kernel: [drm] Initialized i915 1.6.0 20150731 for 0000:00:02.0 on minor 0 kernel: [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A kernel: [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun kernel: i915 0000:00:02.0: fb0: inteldrmfb frame buffer device ===
Hardware:
=== [~]$ lscpu | grep "Model name" Model name: Intel(R) Pentium(R) CPU G2020 @ 2.90GHz
[~]$ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) ===
and xrandr output (with 4.3 kernel):
=== [~]$ xrandr --listproviders Providers: number : 1 Provider 0: id: 0x47 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 4 outputs: 4 associated providers: 0 name:Intel
[~]$ xrandr Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767 DP1 disconnected (normal left inverted right x axis y axis) HDMI1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm 1920x1080 60.00*+ 50.00 59.94 1920x1080i 60.00 50.00 59.94 1680x1050 59.88 1400x1050 59.95 1600x900 60.00 1280x1024 60.02 1440x900 59.90 1280x800 59.91 1152x864 59.97 1280x720 60.00 50.00 59.94 1024x768 60.00 800x600 60.32 720x576 50.00 720x480 60.00 59.94 640x480 60.00 59.94 VGA1 disconnected (normal left inverted right x axis y axis) VIRTUAL1 disconnected (normal left inverted right x axis y axis) ===
Ideas?