I have similas issues with a Colorfly e708q1 tablet, with Arch and kernel 
5.x . I have completely no AXP20x support, although it's in the kernel, but 
the device is fully missing from the /dev /sys and so on. So i have no 
power management.
Does anyone know how to get the AXP work...?
Thanks in advance :)

On Monday, March 28, 2022 at 4:16:10 AM UTC+2 [email protected] wrote:

> Hello,
> I'm trying to run mainline Linux kernel on a Q8-format A13 tablet. In 
> particular, along with Alpine Linux initramfs and packages.
> I have three of them, one is a Q8_V07 and two are identical Q8A_V1.2. 
> I'm compiling v5.15 mainline on sunxi_defconfig and U-Boot v2021.10 on 
> q8_a13_tablet_defconfig. (Newer U-Boot crashes with "initcall sequence 
> failed", but that's already a different topic). Device trees for both 
> images are sun5i_a13_q8_tablet. I did change some config options, but the 
> problems described below aren't affected by my changes.
>
> There are numerous problems regarding the LCD and USB. I thought I could 
> ask here for help, because I'm running out of options.
>
> [Q8, Q8A problem]
> The LCD works perfectly fine in U-Boot. Booting the kernel corrupts the 
> image (white flashes, colorful stripes, etc), unless I use the DTB straight 
> from U-Boot, which makes it work. 
>
> [Q8A problem]
> A much bigger issue is the USB. On the Q8A tablet, for some reason, the 
> device just turns off when booting the kernel. I found that it happens 
> whenever LDO3 is being turned on (USB1 VCC). The display goes black, the 
> CPU stops responding, just like the power was cut. I can confirm it on both 
> Q8A tablets (so it's not a hardware-faulty device), *however* this doesn't 
> occur on the Q8. The Q8A power cut happens during hardware init, about 
> 1.5sec after the kernel starts (also happens with Alpine generic-arm7l 
> kernel, though in phase of loading kernel modules, 30sec later). LDO3 is 
> responsible for WiFi USB card, so I just disabled it in DTB for now.
>
> [Q8, Q8A problem]
> With LDO3 disabled, the kernel boots fine on all three devices. And on all 
> three of them, USB just doesn't work. It finds the two "Linux foundation" 
> root HUBs, and nothing else. OTG power isn't applied (dmesg even states 
> clearly "vcc-vusb0: disabling"). Devices aren't recognized with a powered 
> USB hub. Plugging the USB at any time does not log anything in dmesg, even 
> after enabling verbose identification. Forcing the power on 
> ("regulator-always-on" for PG12 in DTB) makes no difference, except the 
> power is actually ON. Disabling ID and power detect pins in DTB doesn't 
> change anything. 
>
> On alpine generic-arm7l the same happens, with a slight difference of just 
> one root HUB present.
> USB OTG works perfectly fine in U-Boot. Also with keyboard input, I can 
> type in the console on the LCD.
>
> About the USB1 power:
> In all DTBs I could find, USB1 is powered by AXP209's LDO3. Although, from 
> script.bin files pulled from Q8A and Q8 firmwares, I still see different 
> values. Q8 has it on PG11 in the FEX file, and strangely, Q8A has it on 
> "port:power203" (which probably also translates to PG11). Does PG11 has 
> something to do with AXP?
>
> Now, here's the question. Where should I look in order to resolve these 
> issues? Are there any more debugging options to enable in the kernel? Or 
> maybe should I look for clues in the vendor kernels? Possibly on running 
> Android instances? Or maybe does anyone know why do these issues occur?
>
> I can post more information if you need any. I guess I'm doing something 
> wrong, something probably very little and stupid.. but I can't figure it 
> out by myself.
>
> Thanks in advance 
> Kuba
>

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