Black screen but audio of Steam running in background

[il_mix]

Hi, everyone!

I have an issue with SteamOS.
I've read several "blank screen" discussion, but no one seems to mention that they can hear background sounds of Steam big picture interfaces (so everything is running) like me; looks more like other users have system freeze.

Details:

I'm trying to install SteamOS to my laptop.
Relevant specs:
Processor: Intel® i7-6700hq
Chipset: Intel® HM170 Chipset
RAM: 12GB ddr4
Graphic: NVIDIA® GeForce® GTX 950M with 2GB GDDR5
Monitor used: laptop monitor (no external screen via HDMI/VGA)

I've tried installing several versions of SteamOS. The most promising are the official SteamOS, downloaded from steampowered, and Stephenson's Rocket "Ye Olde SteamOS".

These are the steps I've done and what I've seen with the official version:
1) follow the install procedure
2) terminated the install, the system reboots
3) Debian GRUB; default option runs automatically
4) I see the Debian GNOME desktop, and the Steam install windows pops up
5) system reboots
6) SteamOS flavored GRUB; default option runs automatically
7) after a while, the screen goes blank, I see a big mouse arrow (not the system one, the one you see in Steam big picture) for one second, then blank again. BUT, I can hear the "bubbling" sound of Steam big picture splash screen, and I can then navigate the menu with arrow keys (I can hear the button selection "bubbling" sounds, althought I can't see anything)
So, the system is running, but I can't see the interface.
BUT, I've seen the Debian desktop on step 4, so I think I'm OK with graphic card drivers.
I've tried to kill the Steam process via console (I can access tty conoles, e.g. via Ctrl+Alt+F2) to get access to the desktop, but I don't know which process to kill... I've tried several, but the interface automatically restarts every time.
I think it can also be useful to start the system without automatic Steam startup, or with an automatic startup in desktop version instead of big picture. But I don't know where to set this configuration...

Regarding Ye Olde SteamOS version, I'm not sure about steps 3-6 (I wasn't watching the monitor), but in the end I have the same behavior (Steam running, no video, working audio).

Can someone give me a hint about what to do to correct the problem?


Thanks!
MIX

[Teddy]

If you have access to a tty, can you confirm if nouveau or nvdia kernel module is loaded?

[il_mix]

lsmod lists these modules (nvidia/nouveau related only):

nvidia_drm
nvidia_modset
nvidia
nouveau

[Teddy]

Both of them are in lsmod? I get the feeling that's wrong, nouveau should be blacklisted. I am guessing this could work

sudo update-alternatives --set glx /usr/lib/nvidia
sudo update-initramfs -u

[il_mix]

Did it.
After reboot lsmod doesn't list nouveau, and lists only nvidia. I mean -only- nvidia: no more nvidia_drm nor nvidia_modset.
Awfully, still black screen :(

So... first, what did I just do?
Can it be useful to revert the modification (how?) and simply blacklist nouveau?
Or any other idea?

Many thanks for you support!

[il_mix]

UPDATE
I've reinstalled SteamOS for reasons.
I've tried to manually blacklist nouveau by:
- creating the file '/etc/modprobe.d/nouveau.conf', that contains the line

blacklist nouveau

- run command 'depmod -a'
- run command 'update-initramfs -u'
After reboot, I can see the SteamOS interface!!!
BTW, it is stuck at "Checking for available updates..." :(
I suppose this is a different topic.

Thanks for your hints @Teddy!

[Teddy]

I think you just documented a fix for a bug that has been reported here earlier. Another user had issues with SteamOS on a high end laptop and I suspected this was because of nouveau interfering. Thank you for confirming.

Do you mind sharing what brand laptop we're talking about?

I am assuming the "checking for available updates" comes from the Steam client. AFAIK that should take care of itself.

[il_mix]

Well, I think we can't tak about "bug fix" yet. I'm experiencing some very random behavior.

As said before, I've reinstalled SteamOS, actually using Ye Olde StemOS version, and then applied the fix.
Then, I've tried reinstalling again the official SteamOS version, to check the fix there, and the fix didn't work.
Installed again the same version, and everything worked without fixing, with both nouveau and nvidia modules. (but still stuck at "verifying install", "checking for updates"). Reinstalled again the same, all black and fix not working. Reinstalled Ye Olde version, all black and fix not working.
I can't even...

[Teddy]

I would recommend sticking with the official branch. SteamOS is still experimental and I've seen conflicts with packages/repositories and the client.

What laptop are we talking about? Do you have networking?

[il_mix]

This is my laptop: ASUS K550VX-XX107T
Wireless is not working with SteamOS (or so it seems). I've disabled on bios and working with cable network only (it works, since Debian can download/update the Steam client).
I'll made some more rigorous test, and maybe I can share more reliable info on my SteamOS experience.
In the meanwhile, let me know if reading my laptop specs rings a bell.
Question: is it possible to run SteamOS without autostarting Steam? (in other words, how to access Debian?)

[Teddy]

You can disable the LightDM autologin. Should be documented on the SteamOS community wiki on github.