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Connecting to and from external HDMI causes blank screens
Closed, ResolvedPublic

Description

Connect your laptop to an external monitor. Sit idle for a while and let it lock by itself. Disconnect from HDMI while the screen is still blank and locked. Now wake the laptop by striking a key. The screen is black. You can still log in by typing your password, but you won't see anything until you reconnect to HDMI.

I have Intel 615 graphics, if it matters.

I've messed around with a bunch of different monitors around the office, trying to isolate this. There seem to be a number of issues, perhaps with related causes, involving mismatches between laptop resolution and monitor resolution, whether or not the displays are mirrored, whether or not the laptop or the monitor is in native resolution, and possibly whether or not the laptop lid was closed during boot. All I've managed to replicate consistently is this bug, as reported, but while you're at it, you might want to check on those other issues.

Event Timeline

I just tested this a bit further. I booted the laptop connected to a monitor. Then I disconnected it while still in mirror mode. After that, I let it fall into lock mode with a black screen. As expected, I could not see the password I was typing in until I connected an external monitor. I typed the password, but did not yet hit Enter because I wanted to see what would happen if I unplugged and plugged the HDMI several times in succession, with plenty of resync time in between. I ended up hanging the machine with the password dialog showing after maybe 5 cycles. Maybe this wouldn't have occurred, had I allowed more resync time between plug events. Then again, robust software would not need extra time in order to prevent hanging the machine. Unfortunately, I have no idea where in the stack between me and the hardware the problem actually resides.

I have a similar issue (not sure if it should be a separate ticket). My external display is set to primary. When my screens have been blanked and I unplug the HDMI, I get the login screen background on my laptop but no top panel or login prompt. Typing does not log me in (might have been a number lock issue), nor can I get my pointer to show up on the laptop screen. Plugging the HDMI back in for even a fraction of a second brings the login prompt to the laptop screen.

This was the error when I disconnected:
[drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is invalid, remainder is 23

This is the error when plugging the HDMI back in for a moment:
[drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is invalid, remainder is 191
Raw EDID:

00 ff ff ff ff ff ff 00 04 69 a4 32 01 01 01 01
0f 1a 01 03 80 47 28 78 ea 87 d5 a8 5f ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
testmonkey added a comment.EditedFeb 12 2017, 6:42 AM

Considering that you got the login background but could not see the prompt, which is centered, that sounds like a resolution mismatch between your monitor and your laptop screen, which is not being handled properly when you're logged out. This is a delicate issue because it begs the question of what settings the driver should be able to see when you're logged out, vs. what it shouldn't. (I suppose this is one reason why Solus quite sensibly separates logged in from logged out background images.)

Maybe the checksum errors are just benign side effects of the plug event in the middle of a scanline trace by the video chip. Or maybe not.

aledbf added a subscriber: aledbf.Mar 7 2017, 1:40 PM

The issue described in this ticket also affects me (intel card as well). Besides I need to plug out-plugin the external monitor after a screen lock to 'wake it up'.

Does this issue still persist under a fully upgraded Solus 3?

JoshStrobl moved this task from Backlog to Other on the Hardware board.Oct 26 2017, 3:09 AM

I’ve been completely mobile the last couple of months. However I tried to use HDMI two days ago for audio output and had no HDMI source listed. I’ve not had time to investigate further.

JoshStrobl closed this task as Resolved.Jan 27 2018, 5:30 PM
JoshStrobl claimed this task.

Marking as resolved. If the issue persists, feel free to comment.