Dan Dascalescu's questions

I'm running Ubuntu 20.04 on a Lenovo X1C 7th Gen with 16GB RAM. The swap is set to 2GiB.

Just after entering edit mode on a photo in Google Photos (in Firefox), which I'm pretty sure has a serious memory leak (because I've seen it increase memory consumption and slow down the system), the system froze like this:

It stayed like that for a good 3 minutes, with the mouse cursor barely dragging along (good luck taking a screenshot). Eventually it recovered. As you can see, there was plenty of RAM available.

What was going on, and how can I prevent this? /proc/sys/vm/swappiness is the default, 60.

I have a modern laptop (Lenovo X1 Carbon 7th Gen, Intel® Core™ i7-8665U CPU @ 1.90GHz × 8, Mesa Intel® UHD Graphics 620 (WHL GT2), 16 GB RAM) running Ubuntu 20.04 with GNOME 3.36.2, in a dual-monitor setup. The laptop's internal screen is 2560x1440.

So far, I've been using an older external DELL U3417W monitor, which was running at 3440x1440 @ 50Hz via HDMI without problems, in a Joint Displays configuration (total pixels 2560x1440 + 3440x1440 = 8.6M @ 60Hz and 50Hz respectively).

Yesterday, I replaced the DELL monitor with a 4K monitor, the ViewSonic VP3268-4K. Using the supplied HDMI cable, I can only get 30Hz out of it at 3840x2160, and everything is slow. Not just scrolling text pages, but even typing "aaaaaaaaaaaaaa" in a single-line input field in Chromium lags. That was not the case with the 50Hz display.

The resolution of the new monitor is nothing crazy, only 67% more than the previous one. I don't see any extra CPU consumption. I disabled the laptop's internal screen, to keep only the monitor in a Single Display configuration. Still 30Hz, and the total pixelage is 3840x2160, so 8.3M, less than the internal screen + DELL combo.

Is there a way to enable/force at least 50Hz? I tried forcing the rate to 60, but that just led Ubuntu to considering the display as new (scaling 200%, primary was the laptop) and the refresh rate ended up 30 again.

How can I tell if this is a limitation of,

• the monitor (its specs are vague, "25 - 75Hz"), so that I can return/exchange it. I've been through all its OSD menus, set "Response Time" and "Low Input Lag" to every combination, incl. "Ultra fast", and ran xrandr after each. Disabled HDR10, Film mode. Tried View Mode -> Game -> FPS1, FPS2; etc. 30 Hz was the max for 3840x2160.
• the HDMI cable that came with it (I tried another one, same result, and both cables are driving the DELL monitor @ 50Hz). Both cables are marked "High Speed HDMI" (with or without Ethernet).
• Ubuntu (I don't have Windows to try but I could flash another distro that's supposed to have better 4K monitor support?)
• drivers or whatever else

xrandr output:

Screen 0: minimum 320 x 200, current 6400 x 2616, maximum 16384 x 16384
eDP-1 connected 2560x1440+0+1176 (normal left inverted right x axis y axis) 309mm x 174mm
   2560x1440     60.00*+  59.99    59.99    59.96    59.95  
   1920x1440     60.00  
   1856x1392     60.01  
   1792x1344     60.01  
   2048x1152     59.99    59.98    59.90    59.91  
   1920x1200     59.88    59.95  
   ...
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected primary 3840x2160+2560+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     30.00*   25.00    24.00    29.97    23.98    29.98  
   1920x2160     59.99  
   3840x1080     59.97  
   1920x1200     59.95  
   1920x1080     60.00    60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1920x1080i    60.00    50.00    59.94  
   1600x1200     60.00  
   1680x1050     59.88  
   1280x1024     75.02    60.02  
   1440x900      59.90  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1440x576      50.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08  
   720x240       60.12    60.05  
DP-2 disconnected (normal left inverted right x axis y axis)

From ~/.config/monitors.xml:

  <configuration>
    <logicalmonitor>
      <x>2560</x>
      <y>0</y>
      <scale>1</scale>
      <primary>yes</primary>
      <monitor>
        <monitorspec>
          <connector>HDMI-1</connector>
          <vendor>VSC</vendor>
          <product>VP3268-4K</product>
        </monitorspec>
        <mode>
          <width>3840</width>
          <height>2160</height>
          <rate>30</rate>
        </mode>
      </monitor>
    </logicalmonitor>
    <logicalmonitor>
      <x>0</x>
      <y>1176</y>
      <scale>1</scale>
      <monitor>
        <monitorspec>
          <connector>eDP-1</connector>
          <vendor>LGD</vendor>
          <product>0x05ee</product>
        </monitorspec>
        <mode>
          <width>2560</width>
          <height>1440</height>
          <rate>59.997714996337891</rate>
        </mode>
      </monitor>
    </logicalmonitor>
  </configuration>

The entry for the DELL was

      <monitor>
        <monitorspec>
          <connector>HDMI-1</connector>
          <vendor>DEL</vendor>
          <product>DELL U3417W</product>
        </monitorspec>
        <mode>
          <width>3440</width>
          <height>1440</height>
          <rate>49.986808776855469</rate>
        </mode>
      </monitor>

About a week ago, I did a clean install of Ubuntu 18.04.3 Desktop on my 8GB laptop, exactly as in this other upvoted question. I chose LVM and encryption.

Somehow, Ubuntu decided to create a very small swap partition - only 1GB. This results in frequent freezes as the OS is thrashing the tiny swap partition when more than a few applications are open. (I still don't understand how in almost 2020, Ubuntu still doesn't have any way to warn the user of running out of memory ?).

Anyway, I followed the steps to create a swap file. The file is used after swapon, but not after reboot:

$ sudo swapon -s
Filename                Type        Size    Used    Priority
/dev/dm-2                               partition   1003516 0   -2

$ ls -al /swapfile
-rw------- 1 root root 17179869184 Dec  3 13:39 /swapfile

$ grep SwapTotal /proc/meminfo
SwapTotal:       1003516 kB

Also, I don't see the swap partition in Gparted after booting from a rescue USB stick:

1. What is going on here with the partitions? What are those <1GB partitions, especially the second one, and why are they taking up disk space?
2. How can I get rid of the swap partition, wherever it may be?
3. How can I force Ubuntu to use the swap file?

Note that I installed Ubuntu 18 last year, and didn't run into this silly situation. This looks like a regression - is there a Launchpad ticket tracking it?

Similar to What's the right terminology for Unity's UI elements?, what is the terminology for the various elements in GNOME Desktop? In particular,

• Is there a "HUD"?
• What's the name of the "Type to search" field and ensuing window? The Visual overview of GNOME page says that "Dash" is something else.
• Bonus question: why didn't GNOME use standard terms like "taskbar"?

When creating a .desktop shortcut to an appimage, the Icon is not automatically extracted from the appimage, even though the appimage does contain an icon.

1. Is this a limitation of the DE? Is there a bug tracking it? I'm using GNOME in Ubuntu 18.04, and forcing the user to hunt for an icon file, place it in some path, then link to it from the .desktop file, is silly.

2. What's an easy way to extract the icon from that appimage?

I like Ubuntu 18.04/Gnome 3.28 so far, but there's one thing that bothers me: when pressing Super to search for something (e.g. a recent file), there's a jarring transition from my current window to the desktop with the all the window previews exploded on it, then the windows disappearing as the search results are displayed:

(See video)

This is not just slow, but annoying. I don't need to see all my open windows when I just want to launch a new application of open a file.

What I want is just the search results overlaid onto the foreground window, the way Unity does it:

(See video, though this isn't a great demo as the guy didn't have any windows open at that point in the video; anyway, imagine there's a browser window open and you press Super - the window will stay open)

This is a lot faster than what Gnome does.

How can I get this behavior out of Gnome? Or do I need to install Unity?

By popular request, I'm asking how do AppImages, which are read-only and stay compressed, store their settings.

I'm trying to get an Ubuntu VM to run well in the latest VirtualBox (5.2.2), which I installed by running sudo ./VboxLinuxAdditions.run. The problem is I keep getting this error message when the VM starts:

VBoxClient (seamless): failed to start. Stage: Setting guest IRQ filter mas Error: VERR_INTERNAL_ERROR

The host is Ubuntu 16.04.3. I've tried two Ubuntu 17.10 distros (Lubuntu and Budgie). Both failed with the same error.

Being unable to run Ubuntu on Ubuntu should be a P0 critical issue for Oracle. What am I doing wrong?

I wanted to dismount a volume and lsof showed kactivitymanagerd had a directory open (cwd DIR) that I hadn't worked in since yesterday. I might have used Kate to edit a file in that directory. I don't use KDE.

What does this daemon do, and why would I want it running on my computer? Its GitHub project doesn't provide end-user information.

How can it be disabled?

I have an Amazon Echo and a laptop running Ubuntu 16.04.1. I can successfully pair the device via Bluetooth (the Echo says Now connected to <my machine's name>), but when I test the sound, nothing is heard. The volumes are high enough and other devices can connect to the Echo just fine.

Here's the dmesg output:

$ dmesg | grep -i blue
[   12.419477] Bluetooth: Core ver 2.21
[   12.419491] Bluetooth: HCI device and connection manager initialized
[   12.419494] Bluetooth: HCI socket layer initialized
[   12.419497] Bluetooth: L2CAP socket layer initialized
[   12.419502] Bluetooth: SCO socket layer initialized
[   12.473236] Bluetooth: hci0: read Intel version: 370810011003110e00
[   12.480889] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[   12.839251] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[   13.386452] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   13.386456] Bluetooth: BNEP filters: protocol multicast
[   13.386460] Bluetooth: BNEP socket layer initialized
[   16.473284] Bluetooth: RFCOMM TTY layer initialized
[   16.473292] Bluetooth: RFCOMM socket layer initialized
[   16.473297] Bluetooth: RFCOMM ver 1.11
[10944.651128] Bluetooth: hci0: read Intel version: 370810011003110e00
[10944.651133] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[10944.977821] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[24061.878085] Bluetooth: hci0: read Intel version: 370810011003110e00
[24061.887184] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[24062.211121] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[24072.874829] Bluetooth: hci0: read Intel version: 370810011003110e00
[24072.874835] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[24073.196858] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[45209.076985]  iwlwifi videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 serio_raw videobuf2_core btrtl btbcm btintel input_leds bluetooth snd_hda_codec_realtek(OE) snd_hda_codec_generic(OE) snd_hda_codec_hdmi(OE) v4l2_common snd_seq_midi joydev cfg80211 snd_seq_midi_event videodev media snd_hda_intel(OE) snd_hda_codec(OE) snd_hda_core(OE) snd_hwdep lpc_ich snd_pcm snd_rawmidi shpchp snd_seq mei_me mei snd_seq_device snd_timer snd elan_i2c int3403_thermal 8250_fintek soundcore 8250_dw i2c_designware_platform dw_dmac snd_soc_sst_acpi i2c_designware_core dell_smo8800 dw_dmac_core processor_thermal_device spi_pxa2xx_platform int3402_thermal int3400_thermal int340x_thermal_zone acpi_thermal_rel intel_soc_dts_iosf dell_rbtn acpi_als mac_hid acpi_pad kfifo_buf industrialio parport_pc ppdev lp parport autofs4
[55174.636122] Bluetooth: hci0: read Intel version: 370810011003110e00
[55174.646073] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[55174.970198] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[55181.295879] Bluetooth: hci0: read Intel version: 370810011003110e00
[55181.295922] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[55181.670006] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[56551.946597] Bluetooth: hci0: read Intel version: 370810011003110e00
[56551.955475] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[56552.282610] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[98502.038807] Bluetooth: hci0: read Intel version: 370810011003110e00
[98502.038816] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[98502.356833] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[107908.657215] Bluetooth: hci0: read Intel version: 370810011003110e00
[107908.657298] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[107908.985251] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[109042.464364] Bluetooth: hci0: read Intel version: 370810011003110e00
[109042.464372] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[109042.782838] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[109052.807963] Bluetooth: hci0: read Intel version: 370810011003110e00
[109052.807968] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[109053.127969] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated
[127570.876446] Bluetooth: hci0: read Intel version: 370810011003110e00
[127570.953632] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.8.10-fw-1.10.3.11.e.bseq
[127571.270715] Bluetooth: hci0: Intel Bluetooth firmware patch completed and activated

How can I get rid of fonts I'll never use, for locales I'll never need?

Ubuntu's Font Viewer comes with tons of fonts for every locale imaginable - Chinese, Korean, Japanese, Arabic, Urdu, a bunch of fonts called Kacst, some called Qran etc.

With all due respect for those folks, probably even they are only going to need ONE of those regional fonts on their machine, tops. As for the rest of the world, we'll be fine with Latin.

BleachBit cleans up unused localizations, but doesn't clean up unused fonts.

I don't care about the disk space, but these fonts pollute the font space and make selecting the fonts I really want a mess:

For some reason, the latest Kubuntu ships with KDE Plasma 5.5.5, which is at least two minor versions behind the latest stable release of 5.7.4.

How can KDE Plasma be upgraded?

_{(This question was already asked for Kubuntu 14.10 without a good answer.)}

I want to assign a shortcut key to the "Recent documents" Cinnamon applet, but I can't quite figure what the command for the applet would be.

Aside from Unity, which of the many desktop environments support switching among the currently open windows using Super+1/2/3/.../9?

Reasoning

This is especially handy if you often switch among the same few apps, e.g. a browser, a file manager and an editor, but also have other apps open, so Alt+Tabbing to the desired window would take more time.¹

That keyboard shortcut saves me probably 5 seconds per minute on the average, so ~40 minutes a day, and it's supported by Windows 7 as well. Adding custom keyboard shortcuts for the app doesn't work, because pressing the shortcut will launch a new instance of the app.²

^{1. The DE will order the most frequently used windows first, but you have to first look and see how many times you have to press Alt+Tab; while with Super+1 or Super+2, you always know which shortcut goes to one app or the other.}

^{2. Some apps have an option to allow only one instance, but this is the exception rather than the rule, and even in that case, there will be a noticeable flicker of launching the new instance and seeing it exiting immediately.}

I have an extremely frustrating problem with Ubuntu 16.04 LTS 64-bits on my Dell E7450: when I connect a TV over HDMI (tried a Samsung 1080p TV via this 25-ft high-speed HDMI cable with Ethernet support, and also a Visio TV via a 6-ft cable), MOST OFTEN BUT NOT ALWAYS the sound is 2x as slow, and everything else, e.g. video playback, is dragged down to slow-motion.

In other words, testing audio via Speaker Testing goes "Frooont Leeeft" in a low-pitch male voice (the normal is a crisp "Front Left" in a female voice").

After some frustratingly random combination of reconnecting the cable, switching among display mirroring modes and rebooting, the sound returns to normal - as long as the laptop doesn't enter standby mode.

This drives me nuts. Any solutions?

(Not talking about resizing the desktop edition as most other questions do.)

I've installed Ubuntu 14.04.1 server 64-bit in VirtualBox 4.3.10 (not .20, which apparently isn't compatible) but the screen won't grow beyond 80x50 or something like that:

I've gone through the steps to install the official guest additions, which ultimately fail with an X.Org error. Well, duh. I need a server box, without a window manager.

How do I make the terminal match the resolution of the VirtualBox window?

UPDATE

I've since installed virtualbox-guest-utils and rebooted numerous times. The "Autoresize Guest Display" option is still disabled.

Has nobody else encountered this problem? Or do you just ssh into the box?

This is a follow-up to Memory limiting solutions for greedy applications that can crash OS?: ulimit and cgroups are not user friendly, and besides, wouldn't work with applications that spawn separate processes, such as Chrome/Chromium for each new (group of) tabs.

The simple and effective solution, used by Windows 7 actually, is to warn the user that the OS is running low on memory. This simple warning pop-up has prevented me from having any low-memory-caused system freeze in Windows, while I kept running into them on Ubuntu distros that I was testing live (where the RAM-mounted disk would eat up 2GB alone).

So, is there some way to automatically warn the user that the available RAM is nearing zero, without the user having to keep an eye on some memory monitoring gadget? Surely Conky could be configured to do that?

I've updated the Unity article on Wikipedia and need a better reference from the source on the Dash. However, I can't seem to find any sort of official definition of just what exactly what the dash is, anywhere on canonical.com, ubuntu.com, or Mark's blog. What the heck.

To clarify, I'm looking for a post from a source, be it Canonical or a 3rd party but reliable source, that focuses primarily on the Dash. This post comes close, but it's more of an essay on the progress of the work on Dash, rather than an intro/presentation/definition.

Aside from Unity, KDE and Cinnamon, which of the many desktop environments support incremental search among the start menu items, including not just applications, but recent documents?

That is, which DEs integrate semantic search systems like Synapse (no longer maintained), Kupfer or GNOME Do?

LXDE and XFCE do not, for example, though in XFCE you could press Alt+F2 and click the down arrow to search among installed applications (recent documents aren't added to this menu).

(Ideally, this menu would be activated when the Win/Super key was released, which seems almost impossible to achieve, though Cinnamon does it)

I find it much faster to identify a window in the taskbar (window list) by its icon,

rather than by its text:

The problem with most graphical interfaces I've switched among is that they don't group windows, and if you have more terminals or file managers, they'll just clutter the taskbar and you won't know which is which. Windows 7 offers a relatively elegant solution to this by grouping similar window icons together.

Question: What Linux desktop environments have this functionality? If addons exist that provide it, that's alright.

For reference, a Cinnamon applet that sort of does this is Window List With App Grouping.