I have a question about the pin connections of the HIMAX chipset in the DTS for the board in the ‘IPC-M10R800-A3568J
AI Industrial Tablet PC’ (AIO-3568J Board) . In the DTS only the RESET PIN is connected to the PCA9555 extender chip and the IRQ PIN is connected to the RK3568 pin “RK_PC1”. The kernel reports that “himax,gpio_3v3_en” is not valid. My application turns off the backlight after 30 minutes (/sys/class/backlight/backlight/brightness == 0). After a few hours I noticed that the touchscreen stopped responding (froze) but my QT application continued to work normally (log output of the background jobs). I used a simple C program to read the device /dev/input/event2. This C test program also doesn’t respond when I tap the touchscreen with my fingers.
So my question is:
Is the HX83102-B built into the tablet?
How is the HIMAX chip supplied with power.
Is there a schematic plan for the IPC-M10R800-A3568J tablet (AIO-3568J board)?
So, after a long analysis of the HIMAX driver, I found the cause. The driver registers event handlers for ‘screen blank’ in the FB/DRM subsystem. So far so good. But some ‘grr’ thinks that you have to switch off the power supply of the touch panel (3v3 GPIO) in the ‘Screen Blank’ event. The big question is, how high is the probability that the chip will realize without power that the user is tapping the touch panel with their finger?
The answer: Never!!!
I love programmers who seem to switch off their brains when they ‘hack’.
After I DIDN’T call himax_common_suspend() and himax_common_resume(), the panel responds immediately when tapped with my finger. By the way: xx_supend and xx_resume are intended for the kernel PM subsystem, not for blank screen events!
Since HIMAX is not listed in the maintainers list, I strongly assume that some ‘grr’ from FF put the driver including code for the MCU FW programming in the kernel tree.
I am also looking for the exact answer to this topic and am wordle nyt very unhappy that till now I have not found a solution to it, I would be very happy if someone here can give a best solution to solve it.
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