Embedded QT5 Keyboard auto-repeat does not work - qt

After a hardware upgrade, an update from QT4 to QT5 was necessary. The hardware contains a small keyboard and under QT4 I was able to activate automatic repetition with the following environment variable:
QWS_KEYBOARD='LinuxInput:/dev/input/event0:repeat-delay=500:repeat-rate=200'
On QT5 I tried the same thing with
QT_QPA_EVDEV_KEYBOARD_PARAMETERS='/dev/input/event0:repeat-delay=500:repeat-rate=200'
The keyboard works, but the automatic repetition of keys does not work. Is there something I have overlooked?

After all, the problem is now solved. If anyone stumbles across this thread, this was the solution in this case:
The hardware upgrade also required a Linux kernel upgrade. And in the device tree the 'autorepeat' attribute for the gpio keys driver was missing.

Related

How to use cl2.hpp with AMD GPU and rocm

I've been developing with OpenCL on my Laptop for a while now, but want to move to my more powerful desktop pc with an AMD GPU. I followed the breadcrumbs through APP SDK (which is apparently gone) through amdgpu-pro drivers (which completely crash my system) and landed on rocm. I can't install the drivers on my kernel, but the rocm-dev seems to work fine. Unfortunately I can't seem to be able to use Khronos' cl2.hpp anymore, as it doesn't seem tk link to any cl calls. I would like to still be able to work with the Intel CPU on my laptop without completely rewriting my code. Is it possible to easily integrate cl2.hpp into my rocm installation?
Found it. I wasn't linking against the libOpenCL.so correctly. I am using cmake and set OpenCL_LIBRARY to the amdgpu-pro lib directory rather than the actual library file. Apparently FIND (OpenCL) doesn't work with the /opt paths rocm and amdgpu provide.

intel_iommu , what is it?

One of my customers had a problem with a Xeon E5 machine: they were having one gpu (I believe it was an NVIDIA one) hanging and they solved by adding the
intel_iommu = igfx_off
in the grub loader.
What is this value and what does it? I read around but couldn't just figure that out in simple terms
Quoting from the "Intel-IOMMU.txt" file included in the Linux kernel documentation:
"If you encounter issues with graphics devices, you can try adding option intel_iommu=igfx_off to turn off the integrated graphics engine. If this fixes anything, please ensure you file a bug reporting the problem."
Apparently the GPU in this case was not working properly with the DMAR (DMA Remapping) feature provided by the Intel chipset. Using the "igfx_off" parameter allows the GPU to access the physical memory directly without going through the DMAR.
The purpose of the DMAR feature is to enable things like direct assignment of hardware to virtualized guests. If you have to use the "igfx_off" parameter then you probably won't be able to use this GPU in such a direct-assigned virtualization scenario.

QTCreator segfault after 1st run

I've recently had a horrible problem with QTCreator. After the first time of running the program, ALL debugging instances segfault upon constructing the MainWindow object. Even if i make a blank QTwidget project and run in debug (without editing a single bloody thing), i get a segfault.
This persists after dozens of reinstalls. I have tried both the SDK as well as the IDE and library seperately. The version of the library is irrelevant, i always get the seg fault and its only on my tower. My laptops work just fine.
Does anyone have any possible solutions? Any help will be appreciated.
I needed to run QtCreator in admin mode in order for GDB to function properly.
Without knowing more (please answer to cbamber85's comment), such issues are known to be caused by uberprotectious anti-virus solutions or other software that hooks into places where GDB would usually hook in (Vendor OS-'enhancement' tools are infamous for doing that). This is a known Problem with GDB.
You could try to disable your virus scanner or remove/unload/remove from autostart the vendor tools and try again.
If that doesn't work, the content of the debugger output log pane (Windows > Views > Debugger Log) would be interesting.

How to programatically change the output mode of an intel gma450 graphics card to clone

I would like to change the output mode of an Intel GMA450 based graphics chip to "cloned" mode.
Since the environment is a Windows Embedded Standard and only one of the connected monitors might be visible for the enduser, I would like to either permanently set the output mode to cloned or reset it continuously to cloned mode in case the actual mode differs (e.g. after a reboot, disconect/reconect of the second monitor or by other means).
Is there a way (Registrykey, API for the Intel driver, Win-Api) to change the display mode to cloned / dual output programatically?
Update:
I found the SDK for the IEDG driver it seems that I might be able to programatically set the resolution, clone mode etc.
However, I can't find the SDK or any information for the driver I am currently using: IntelĀ® Graphics Media Accelerator Driver for Windows* XP, version 14.32.4.4926.
This isn't a good answer, but it might get you headed in a direction to figure it out.
My last laptop had an external monitor connected, and the Intel drivers would often be confused about the orientation of the secondary after a reconnect or a reboot. I got tired of dealing with that and tried to fix it programatically because the clicks were too many in the GUI. Select this monitor, select rotation, select other monitor, select rotation, apply, arrange, apply, wait...
I spent about a day on it (ahh, the days of being an employee vs. self-employed!) and the solution I found was to use a program to compare the registry (regshot perhaps?) to discover what keys were involved in the correction (what they were before versus what they were after) and then there was an intel-provided exe that forced the driver to reset based on the registry-- the exe was essentially like pressing the "apply" button in the gui. I was running XP and if I recall, the gui management was for configuration of the Intel Graphics Media Accelerator Driver for Windows XP as well. So the final solution became a cmd file on my desktop that would apply a REG without confirmation and then run an exe with some parameters.
Now, I don't have that laptop (they didn't let me walk out the door with it when I quit!) and I do not remember the specifics on the exe that was required to do the reset. Just changing registry keys didn't spontaneously cause it to take effect-- there was an api call involved, which I just handled with their exe. I know that isn't a lot to go on, but something tells me the file was in the driver package, or somewhere on the drive already, and I just found it. Running it at the command line gave options. Like /reset.
I hope that helps you a little. Be sure to post back if you figure it out.
Also post back if I'm completely mistaken and it didn't happen like this at all. But that's the way I remember it. :)

Ubuntu, Qt and licencing

We have a website that we are planning to distribute in a device. It is basically a big web site with lots of pictures and information. The web site is already built using some flash and javascript. I am thinking on using ubuntu for this. My plan is to install ubuntu( server, maybe!) without a graphical enviroment( Gnome, KDE, etc...) and start a browser like firefox using X servers. I have already tried this using
Code:
xinit firefox
It works and loads firefox fine. I am also thinking to build a Simple UI that will be launched at start. This UI will have a button to start this website and maybe other programs.
I hope I made myself clear.
I would like to know what do you guys think about this? Does it sound like something feasible? Do you think its a good idea to do this way? Do you have any suggestions?
It terms of licensing I don't understand well. I know ubuntu is licensed mainly under GNU GPL and I know is open source. I know that you are required to have any modifications available. However I am not sure if that includes the source code for the web site or any other proprietary application that i create and include. My understanding is that you only need to have open source any changes made to the OS but not any configuration after it has been installed.
What about Qt which is liscenced GNU LGPL v. 2.1? Do i need to release the code for the UI i make or is it only the code for any changes made to Qt itself?
Thanks in advance to anyone that reads this. I have read a lot on this but I am not so sure i got it right. I would like to know if I am at least in the right path.
Any help will be appreciated.enter code here
Ubuntu is GPL - if you make any changes to the Ubuntu (or rather linux) kernel itself then you have to offer those changes to anyone you distribute Ubuntu to - that has nothing to do with any applications or data you use on the operating system.
Qt is LGPL - you can use Qt to make any application you want without releasing anything about your application. You only have to release any modifications you make to the Qt source code yourself - which you are unlikely to do.
You don't need Qt for any of this, you can have a browser run full screen at startup in Ubuntu (or any other linux), and you can have a simple start page which will also start other local apps with just html - this may be a lot easier.
There are also "kiosk modes" for most browsers which limit what features and tool bars are present so you can prevent users quitting the browser or loading/saving other data.
Finally check out xubuntu - it's a version of ubuntu with X but without Gnome or KDE
IANAL, but with LGPL you can dynamically link to Qt and not be required to license your own sources under LGPL.
The general rule of thumb is that your end user should be able to take code of LGPLed component, make modifications to it, and have your proprietary code work with it. This also means you can link statically to LGPLed code if you provide at least object files of your own code, so they can be relinked.
For linux I suspect the answer is yes as well, but I can't say anything specific.

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