hsivonen's questions

I have a PC whose HDMI ports are connected to the Intel GPU integrated into Core i3-4010U. It's running Ubuntu 16.04 with the latest updates. (Upgrade to 18.04 is offered but fails before any packages get installed; resolving that is a whole other issue.)

Previously, HDMI audio output has been available in the Sound setting panel (and has worked). Now it no longer is available in the Sound setting panel. I've both disconnected and reconnected the HDMI cable and applied updates after last witnessing HDMI audio working, so I'm not sure if I should blame disconnecting and reconnecting the cable or if I should blame software updates. (The HDMI cable and the device at the other end of the cable are the same as before.) I haven't made any other changes that could possible affect audio. Rebooting does not resolve the problem.

lspci shows both what I assume to be the GPU-integrated audio device and what I assume to be the S/PDIF / analog audio device:

00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev 09)
00:1b.0 Audio device: Intel Corporation 8 Series HD Audio Controller (rev 04)

What kind of steps should I take to get the HDMI output option restored?

Recently (in December 2018), function keys F3, F4 and F5 broke for a specific keyboard in Gnome on Wayland on Ubuntu 18.04 such that pressing the keys does not result in the function key being passed to the app but results in an overlay showing ? (flipped horizontal).

It doesn't happen with a different keyboard. With the affected keyboard it happens with multiple computers.

What kind of per-keyboard state could result in these three function keys mapping to something that Gnome reacts to with a ? overlay?

On Ubuntu 17.10 using Nvidia Quadro M2000, when the (external) screen stops consuming the DisplayPort data stream (either because the screen is turned off or a different input is chosen on the screen in order to view the desktop of another computer connected to the same screen), the graphical session is terminated, including all processes that were started from the graphical session.

This happens both with Nouveau (both Wayland and X) and with the Nvidia proprietary driver (nvidia-384).

This didn't happen with Ubuntu 16.04 and doesn't happen with Windows or Mac.

Terminating the graphical session like this is, obviously, extremely undesirable.

How can I make Ubuntu 17.10 not terminate the graphical session when the screen stops consuming the DisplayPort data stream?

It seems that Ubuntu Touch (Vivid on Nexus 5) goes into an extremely slow (power-saving?) scheduling mode when the touch sensor has been idle for long enough for the screen to turn off.

This makes the phone unusable for running compilers and benchmarks over ssh, which happens to be my use case.

Is there a way to tell Ubuntu Touch to run the scheduler in the same mode as when the screen is awake when the screen isn't awake but I'm using the phone over ssh?

I want to configure an Ubuntu (Xenial) box as an IPv4 and IPv6 router. (I have IPv4 working already.)

I intend to use dnsmasq to distribute globally routable IPv6 addresses via RA. However, to do that, I first need to get the Ubuntu box acting as the router to fetch a prefix via the WAN interface and to assign it to the LAN interface.

What's the best way to do this in Xenial?

I can find old instructions that involve using the WIDE DHCPv6 client, but it appears that the wide-dhcpv6-client package in Xenial is from 2008 and upstream over on SourceForge doesn't have anything more recent, either. It seems scary to use network-facing software that's written in C and has been abandoned by upstream for years.

As of Xenial, what's the recommended way of fetching a Prefix Delegation prefix via the WAN interface and assigning it to the LAN interface?

(In case it matters, the ISP says that it hands out prefixes of /56 from which the customer's router is supposed to prepare potentially multiple /64 subnets.)

I have a computer running Ubuntu Server (14.04 but I want to upgrade to 16.04 when it becomes available) with two Ethernet interfaces and one WiFi interface.

The interfaces are:

• Ethernet towards WAN: p2p1

• Ethernet towards LAN: eth0

• WiFi towards LAN: wlan0 (Intel Corporation Wireless 7260, driver: iwlwifi)

I'd like to do the following:

• Set up wlan0 in the access point mode with WPA2 encryption in the 802.11 b/g/n mode. (I don't mind enabling 802.11a, too, but I don't need it. I need 802.11n and b/g legacy.)

• Bridge wlan0 and eth0 together as br0.

• Use DHCP to configure an IPv4 address for p2p1.

• Set up a DHCP server to assign private IPv4 addresses to hosts connected to br0.

• Set up NAT between br0 and p2p1 for IPv4 traffic.

• Use DHCPv6 to fetch an IPv6 prefix for p2p1.

• Set up router advertisement to assign IPv6 addresses under the prefix to hosts connected to br0.

• Route IPv6 traffic between p2p1 and br0.

• Set up a caching DNS server and advertise it as the DNS server to hosts on br0 (but block queries from p2p1).

• Set up firewall rules that block all CIFS/SMB, possibily other insecure Windows traffic and CUPS printing between the br0 LAN and the p2p1 WAN.

• Set up whatever other firewall rules are considered best practice while not preventing efficient Skype, WebRTC and push notification traffic between WAN and the hosts on the br0 network.

This should be a basic "turn an Ubuntu box into an IPv4+IPv6 home router" kind of thing. I've done a lot of searching already, but I've failed to find a guide that matches my needs. In particular, I have trouble finding guidance for setting up iwlwifi-based wlan0 with WPA2 in the AP mode and then using that as part of a brige interface. (I found guides that talk about WEP or of using wlan0 as the WAN interface that connects to an AP as a client or explicitly using Atheros drivers as opposed to iwlwifi.) Also, I have trouble finding guidance for the IPv6 part. Superficially, it looks like some combination of bridge-utils, hostapd and dnsmasq could address all of the above. Maybe.

Any pointers to a guide that already covers this or other advice on how to proceed?

I'm trying to use a passphrase-protected GPG key with Obnam, which invokes gpg (1.4.x on Ubuntu Server 14.04) in batch mode. gpg can't ask for the password in batch mode. All gpg-agent stuff that I find seems to involve a GUI dialog, but I'm using Ubuntu Server over ssh and the server doesn't have x.org installed.

What's a non-GUI equivalent of ssh-add for GPG? That is, it'd like to invoke something that works in the terminal to cache the passphrase or the unlocked key in RAM and then invoke obnam, which in turn invokes gpg in batch mode, and have this work.

I have mouse keys enabled on two computers running Ubuntu 12.04. On one of them, the cursor speed is reasonable. On the other one, even when using the same keyboard, the cursor moves unbearably slowly. Setting the key repeat speed to max does not help. Setting the mouse speed to max doesn't help. Setting the touchpad speed to max does not help.

Where's the setting for the cursor speed with mouse keys?

When installing Wine on 64-bit Ubuntu 12.04, both 64-bit support and 32-bit support get installed. If I run wine foo.exe where foo.exe is a 64-bit-aware installer, it thinks it's on 64-bit Windows. This would be fine if this mode didn't fail, but in my case, it does (yet the Wine database suggests the app I'm trying to install should work, presumably as a 32-bit app).

How do I tell Wine (and Winetricks) to use Wine in 32-bit-only mode?

In 11.10, the Unity alt-tab switcher brought all the windows belonging to an application to the front when switching to the application like on Mac (unless you waited for long enough that the app's switcher entry expanded to a window selection in which case you got to select which window to switch to).

In 12.04, switching to an app with multiple window open (in the same workspace) brings to the from one of the windows. (I see no logic in which one is brought to the front.)

How do I, under 12.04, revert to the alt-tab behavior of 11.10 so that switching to an app brings to the front all the windows of that app?

What apt incantations do I need to use to download the source packages for all the installed packages into a directory? (The use case is GPL compliance when giving an installed Ubuntu system to another person along with a computer.)

I have a Shuttle SX58H7 computer (Intel X58 Express board, AMI BIOS version 08.00.16) with Intel Core i7 950 and GeForce GT 210 Silent (nvidia proprietary driver).

Under Karmic (64-bit), hibernation worked fine. Under Maverick, the computer goes to hibernation but when woken, USB and display don't come back and sshd doesn't respond, either. Sometimes when waking from basic sleep (as opposed to hibernation), sshd does come back and the computer can be reached from the network. IIRC, the regression happened when upgrading to Lucid.

Is there a know workaround that would restore the hibernation capability that existed under Karmic?