ScreenSaver Qt 5.15 using linuxfb plugin
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Hi everybody,
Let me introduce myself. My name is John and I'm programmer.
I'm going crazy over this issue and I don't know who to turn to.
A lot of years ago, with Qt 4.8.7 I can be able to blank and unblank screen without any problem.Now, with new kernel ( well, 5.10 is quite old ) and Qt 5.15 it's impossible to turn off the screen.
I would normally access this variable /sys/class/graphics/fb0/blank and it works properly, but now no.The same hardware with old system, this option works but the same system with new BSP, it doesn't work.
Could anybody any idea or advice about how to do it?
I don't want a solution, I just want a clue to keep investigating.Best regards.
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Hi,
Did you check that if the blanking is still working when using the command line directly ?
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Which backed are you using ? Both in Qt 4 and Qt 5 ?
The underlying architecture has changed quite a lot between the two.
Also, do you have the same issue if you run your Qt 4 application with the new kernel ? -
Hi,
The old system has Qt4.8.7 and kernel 4.18. --> sys/class/graphics/fb0/blank works properly!!!!!
The new system has Qt 5.15.14 and kernel 5.10 --> sys/class/graphics/fb0/blank fail !!!!!!!I'm going to run that test you mentioned, Qt 4.8.7 and the new kernel, but honestly, I don't think I'll have the same problem with Qt 4. Anyway, I'll try to run that test.
And thank you very much for your support.
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Thsi is the result of my test...
Kernel 5.10 and Qt 4.8.7 --> sys/class/graphics/fb0/blank works properly!!!!!
Kernel 5.10 and Qt 5.15.14 --> sys/class/graphics/fb0/blank FAIL!!!!And more curious with the second case. if I before turn off the screen from terminal and then execute tje Qt app, Qt return a segmentation fault due linuxfb plugin !!!!!
What??? in short, QT 5.15 take the control in exclusive mode totally.
