Arch Linux

descrip

Member

Registered: 2015-03-14

Posts: 9

[SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Hi, I'm using an Acer C720 Chromebook running Arch. Since the screen is small I'm using a TV as a monitor by HDMI cable. It's been working for a few months now but it suddenly stopped working today. xrandr no longer detects an HDMI output.

Output of xrandr:

Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
eDP1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 256mm x 144mm
   1366x768      60.00*+
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Before, xrandr would list the monitor as HDMI1.

Output of lspci:

00:00.0 Host bridge: Intel Corporation Haswell-ULT DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev 09)
00:14.0 USB controller: Intel Corporation 8 Series USB xHCI HC (rev 04)
00:15.0 DMA controller: Intel Corporation 8 Series Low Power Sub-System DMA (rev 04)
00:15.1 Serial bus controller [0c80]: Intel Corporation 8 Series I2C Controller #0 (rev 04)
00:15.2 Serial bus controller [0c80]: Intel Corporation 8 Series I2C Controller #1 (rev 04)
00:1b.0 Audio device: Intel Corporation 8 Series HD Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 1 (rev e4)
00:1d.0 USB controller: Intel Corporation 8 Series USB EHCI #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation 8 Series LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 8 Series SATA Controller 1 [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 8 Series SMBus Controller (rev 04)
00:1f.6 Signal processing controller: Intel Corporation 8 Series Thermal (rev 04)
01:00.0 Network controller: Qualcomm Atheros AR9462 Wireless Network Adapter (rev 01)

I've tried to connect the Chromebook to another TV, but it did not work. I also tried connecting the HDMI to this TV with another laptop running Windows, which DID work, so it's not a hardware issue with the cable or the TV.

Please help me get my HDMI output working again. Thank you!

Last edited by descrip (2016-03-16 23:47:59)

satanselbow

Member

Registered: 2011-06-15

Posts: 538

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Before, xrandr would list the monitor as HDMI1.

Before what exactly?

Your last update?
The last time your fiddled with your seemingly unrelated config files?
The unfortunate dog mistaking the chromebook as a toilet incident?

Thanks for supplying the logs... but "before"'s aren't very descriptive.. . descrip...

descrip

Member

Registered: 2015-03-14

Posts: 9

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Before nothing.

The last time I had run pacman -Syu was four or five boots before this problem. I also haven't played with any config files. And I don't own a dog. The last time I used the computer before having issues with xrandr was for just browsing the internet. This is why this problem is so confusing to me.

I have run pacman -Syu after getting this xrandr problem (and have also updated AUR packages), but it didn't fix anything. Sorry if I wasn't descriptive enough.

EDIT: One more thing I should probably clarify. The screen on the laptop (eDP1) still works. xrandr cannot detect the external monitor.

Last edited by descrip (2015-03-14 18:27:31)

descrip

Member

Registered: 2015-03-14

Posts: 9

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

I've fixed the problem. In my /etc/default/grub, I used to have the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash add_efi_memmap boot=local noresume noswap i915.modeset=1 tpm_tis.force=1 tpm_tis.interrupts=0 nmi_watchdog=panic,lapic video 1360x768"

When I removed "video 1360x768" xrandr was able to detect the monitor again.

I have no idea why it caused the problem. The laptop screen was 1366x768 but the monitor was 1360x768, and it would cause some clipping issues when using the laptop screen. Following guides online I added "video 1360x768" to /etc/default/grub.cfg to make the laptop boot with 1360x768 resolution even without the monitor to fix the clipping, since its pretty much impossible to tell the difference from 1366x768 and 1360x768.

That was three months ago, but it started acting up today for some reason. Oh well, it's fixed now. Marking as solved. Thank you for your help.

XertroV

Member

Registered: 2015-07-23

Posts: 1

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Just wanted to chime in as I had near identical symptoms with the same graphics controller:

00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)

My machine is a Dell Inspiron 14 7437. I didn't have the corresponding `video` entry in my /etc/default/grub file though.

After an hour of troubleshooting to no avail I tried some percussive maintenance (tapping forcefully near the HDMI port) which seemed to fix the detection issue.

xrandr now shows my HDMI1 output and all is well again. My guess is that these symptoms are consistent with a hardware issue.

descrip

Member

Registered: 2015-03-14

Posts: 9

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Hey Xertov! I never continued this thread, but the issue has popped up again sometimes, just to disappear a few minutes later. Now that you mention it, a hardware issue is pretty likely.

descrip

Member

Registered: 2015-03-14

Posts: 9

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Sorry for necroing, but I've realised that this thread pops up on the top of Google if you search for C720 HDMI issues. This is just an update on what has happened.

Xertov was right -- for me, it is a hardware problem, and tapping the HDMI port usually makes xrandr find the HDMI1 output again. Some anecdotal evidence: whenever I smack the tab key down really hard (during furious coding) while projecting onto a monitor, the screen flickers for a bit. I think it's because the key is next to the HDMI port. Some more furious keystrokes revealed that all of the keys next to the HDMI port, when pressed down with a lot of force, made the screen flicker. Those farther away didn't have any effect. I never realised this before, since I usually attach an external keyboard whenever I project onto a monitor.

There was one time when tapping the outside of the HDMI port did not fix the issue. However, xrandr found the HDMI1 output again after I removed the C720's back cover and applied percussive maintenance to the HDMI port directly. (:

So I guess this problem is all because of the laptop's poor build quality. Which isn't a problem for me, since it's so cheap.

EDIT: Maybe it's not a hardware problem. If xrandr is not detecting the HDMI1 display, disconnect the HDMI cord and power down the laptop and the monitor. While the laptop is shutdown, connect the HDMI port and turn on the monitor. Then turn on the laptop. You might find some success now.

Last edited by descrip (2016-03-18 04:14:06)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,791

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Sorry for necroing, but I've realised that this thread pops up on the top of Google if you search for C720 HDMI issues. T.

It is your thread

Part of the problem with old threads is that the original poster no longer cares.   Not a problem here.

Even better, it sounds solved.  If so, please edit the thread title and prepend [SOLVED] to the topic.

---

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Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
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moinfar

Member

Registered: 2017-11-05

Posts: 4

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

EDIT: Maybe it's not a hardware problem. If xrandr is not detecting the HDMI1 display, disconnect the HDMI cord and power down the laptop and the monitor. While the laptop is shutdown, connect the HDMI port and turn on the monitor. Then turn on the laptop. You might find some success now.

Thanks descrip.

This WORKED for me on ASUS ZenBook (UX433F).
My HDMI output was fine and suddenly it stopped working (no update, not install, no change).
Testing your proposed solution worked for me at the cost of a restart!

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,736

Re: [SOLVED] xrandr no longer detects HDMI output on Acer C720 Chromebook

Glad to hear, however please don't necrobump 4 year old threads.

https://wiki.archlinux.org/index.php/Co … bumping%22

Closing.