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Seeed-Studio / seeed-linux-dtoverlays

Device Tree Overlays for Seeed boards
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reTerminal DM: ch342f chip issue details #84

Closed matsujirushi closed 8 months ago

matsujirushi commented 8 months ago

Hi, I connected a USB-CDC device to the USB of reTerminal DM, but Serial is not recognized. I checked and found that the cdc_acm driver was disabled.

https://github.com/Seeed-Studio/seeed-linux-dtoverlays/blob/master/scripts/reTerminal.sh#L430-L432

According to the comments, it seems that the cdc_acm driver is disabled due to an issue with the ch342f chip. I would like to resolve the issue with the ch342f chip.

Could you please provide more details?

bigbearishappy commented 8 months ago

It's nice of you to help us fix this problem. Here is detail steps to reproduce the issue of ch342f: 1 remove blacklist cdc_acm from /etc/modprobe.d/raspi-blacklist.conf 2 connect you PC and reTerminal DM with a usb-to-rs232 converter 3 opent the terminal of usb-to-rs232 on your computer 4 reboot the system 5 you will get some garbled characters when the system is booting up These garbled characters is not what we want. So we install a new driver to fix this.

If you want to fix this. I think the best way is to take look into the source code of cdc_acm and try to support the ch342f correctly in it~

matsujirushi commented 8 months ago

Thank you for the detailed information.