From time to time I have to restart the kernel in JupyterLab. Where can I see whether the kernel is done restarting in JupyterLab?
There is an indicator in upper right corner of the tab (gray circle). But to be honest it doesn't show detailed status.
I would recommend trying JupyterLab Status Bar extension. It provides statusbar which will display statuses like idle, reconnecting, starting etc.
Related
On behalf of my colleague I'd like to ask if it is possible to rotate the whole QT5 (QT 5.6.1-1) application window. We are using EGLFS as a backend on Sitara TI AM335X platform running Linux framebuffer.
The current situation is like this: we have some application which normally is rotated 90 degrees from end user point of view. As a temporary solution my colleague (the developer of this application) is rotating every element in this window to achieve proper visual effect. Unfortunately this rotation takes a lot of time of CPU.
My question is - is it possible to turn the whole window clockwise? I mean is it possible to do it on EGLFS or QT5 level without rotating every single element in the window?
I tried to exchange x-y dimensions (800x480) of the screen but without success. I have also taken a look into a linux kernel driver sources and I see no possibility to rotate the whole screen. I was thinking about creating some another buffer in memory from which I could copy data with rotation to target memory, but I'm not sure if it is good idea.
Any ideas?
Set the QT_QPA_EGLFS_ROTATION environment variable to 90 or -90. See the documentation.
Rotation on EGLFS platform was afflicted by a bug QTBUG-39959 until version 5.7.x and so the rotation variable was ignored.
The bug is fixed from version 5.8.
ncurses app checks if terminal has been resized. If the size is less than 80x25, then blank the screen and show error message.
If the app has N windows, should all of them be removed with delwin(), or calling clear() would be enough? On the other hand, can already existing windows be later reused after clear() - to refresh and display contents if terminal size became satisfactory - or they should be recreated?
Clearing the windows sounds like the application's behavior rather than ncurses as such. The ncurses library (see resizeterm) will clear areas if the windows increase in size.
The best policy when resizing really depends on what you have inside the windows. ncurses is making reasonably safe changes, but since it has no information about your intention in making some things close on the screen, and others separated, all it can do is to attempt to resize windows so that their contents are preserved. The application can still clear them and start over again — as well as moving windows around on the screen.
It's your decision whether it is simpler to recreate the windows or reuse them.
As long as all of the rebuilding is done before the next repainting of the screen (e.g., with wrefresh), ncurses will make the updates with as little activity as it can.
My question is about the linux kernel. When framebuffer device initializes (I guess it is vesafb), the screen is filled with black color. How can I change that color? What file should I edit? I guess it is something in drivers/video/.
I only know about changing console background (drivers/tty/vt/vt.c), but this is not what I need. VGA Console is turned off.
In case my description is not clear I have a video that shows my system bootup in a virtual machine. After the kernel is loaded QEMU window changes it's size to 640x480 and becomes completely black (0:03-0:04). This is what I want to modify. After it my init is started. It outputs text to framebuffer and then dies, causing kernel panic and reboot in 1sec. Then everything starts over.
The console implementation in vt.c started out as a VGA console once upon a time, but it is now used for all consoles.
(The 'attribute byte' is mapped to whatever the underlying hardware driver actually supports.)
Change the initialization of vc_def_color in vc_init().
Since version 3.12, this can also be changed with the kernel parameter vt.color.
On a computer with multiple monitors where the desktop is not shown on one of them, is there any way to draw on that monitor from a program?
Reasoning: I need to display a variable image full-screen on a separate monitor, without the user being able to disturb the screen with the mouse or without being able to shift windows on top of my image. Example: a computer has one monitor and one projector connected; the monitor shows a "normal" desktop and the projector shows the generated image (say, a color gradient).
The first use would be on Win7, but if a portable solution exists, an X11 solution under Linux would also be nice.
On Linux this is easy using xvfb, a virtual framebuffer. The command is:
Xvfb :1 -screen 0 1600x1200x32
You can run programs on the virtual screen by setting the environment variable DISPLAY=:1
The best part is the user doesn't even have to worry about interfering with the mouse or keyboard. Very useful for testing.
Under Linux, you can also run a second X session on the extra monitor
Xorg :1 -config /path/to/xorg_1.conf
But you'd need to write a xorg_1.conf configuration file to feed in.
I have a touch screen device that is running on windows CE. after 30 second the screen goes off to save power and will come back on it you touch it.
The problem is that randomly when the screen goes off the device will not come back on simply by touching the screen. I have a done a bunch of tests and there is no noticeable pattern to when this happens.
It appears to be performing the same action as when you press the suspend button from the main menu.
I have done some research and found there are 4 power saving settings in the registry and I think I need to disable one to stop the device from "suspending". I never want the device to turn off except for the screen going off, it is always connected to power.
Does anyone know how I can do this or why it is randomly suspending ?
And the entire device is in Chinese So really precise instructions would be appreciated. My application runs on top of the CE.
I know you're after precise instructions, but it's not that simple. The device OEM defined and implemented the power management system for the device, Microsoft only provided the structure for it. The OEM could have implemented power management in any way they sought fit,, and in fact they could have completely ignore the Microsoft-provided framework (wouldn't be the first time an OEM did that). Really you need to get a hold of the OEM and ask them how to prevent the behavior you're seeing or to get something different.
Barring that, you could always play around with the registry entries, but again, there's no guarantee any of them will work. You might look at adjusting power state or the activity timer registry entries.
Playing with the power manager control panel applet might also help (it's probably labelled 电源管理)
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\Timeouts]
"BattSuspend"=dword:0