I bought a new laptop and installed CentOS 7.2 parallel with the original Win10 inside (dual system). When using Win10, I can see HDMI outputs to an extra monitor without problem, but it just shows no signal when I am in the CentOS.
I tried to find the solution on the Internet, but there is no luck. Many questions are about why HDMI doesn't output audio, but mine is it outputs nothing at all.
I then tried to gather some information which might be needed, and I attached the commands and the result as follows.
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080 default connected primary 1920x1080+0+0 (0x17f) normal (normal) 0mm x 0mm Identifier: 0x17e Timestamp: 70549 Subpixel: unknown Clones: CRTC: 0 CRTCs: 0 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: _MUTTER_PRESENTATION_OUTPUT: 0 1920x1080 (0x17f) 159.667MHz *current h: width 1920 start 0 end 0 total 1920 skew 0 clock 83.16KHz v: height 1080 start 0 end 0 total 1080 clock 77.00Hz
lspci -v | grep VGA -A20
00:02.0 VGA compatible controller: Intel Corporation Device 5916 (rev 02) (prog-if 00 [VGA controller]) Subsystem: Pegatron Device 22c4 Flags: bus master, fast devsel, latency 0, IRQ 255 Memory at b0000000 (64-bit, non-prefetchable) [size=16M] Memory at a0000000 (64-bit, prefetchable) [size=256M] I/O ports at 4000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities:  Vendor Specific Information: Len=0c <?> Capabilities:  Express Root Complex Integrated Endpoint, MSI 00 Capabilities: [ac] MSI: Enable- Count=1/1 Maskable- 64bit- Capabilities: [d0] Power Management version 2 Capabilities:  #1b Capabilities:  Address Translation Service (ATS) Capabilities:  #13 00:08.0 System peripheral: Intel Corporation Sky Lake Gaussian Mixture Model Subsystem: Pegatron Device 22c8 Flags: bus master, fast devsel, latency 0, IRQ 255 Memory at b122a000 (64-bit, non-prefetchable) [size=4K] Capabilities:  MSI: Enable- Count=1/1 Maskable- 64bit- Capabilities: [dc] Power Management version 2
I am wondering whether the system can detect the HDMI cable plug-in/plug-out event or not, so I use
dmesg -wH to wait for the event. I found when I plug in the Ethernet cable or USB device, it shows up some information, but there is totally no response when I plug in the HDMI cable. (but it shouldn't be a hardware problem because my Win10 can recognize it)
Then I guess it is a driver problem. I tried the command below.
lsmod | grep hdmi
snd_hda_codec_hdmi 47849 1 snd_hda_codec 137386 4 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_intel snd_hda_core 57760 5 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel snd_pcm 105835 4 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel,snd_hda_core snd 83425 18 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_seq,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel,snd_seq_device
rpm -qa | egrep "hdmi|intel"
According to the information above, I think I have the needed driver (I guess) installed. However, the system cannot recognize it (dmesg no response). Can anybody help me on this issue? Any hint only is also appreciated.