GPIO madness.
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GPIO madness.
Dear Lazyweb, riddle me this:
1. Boot Pi with HDMI monitor attached: works fine.
2. Boot without monitor: all GPIO inputs "flap" about once a second.
3. Plug in monitor: 10 seconds later, inputs start behaving normally.
4. Unplug monitor: remains good. Until reboot.WTF?
Raspberry Pi 4 Model B Rev 1.5, Debian GNU/Linux 12 (bookworm) 12.11. Two different Pis, same behavior.
https://jwz.org/b/yk2F -
undefined oblomov@sociale.network shared this topic
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GPIO madness.
Dear Lazyweb, riddle me this:
1. Boot Pi with HDMI monitor attached: works fine.
2. Boot without monitor: all GPIO inputs "flap" about once a second.
3. Plug in monitor: 10 seconds later, inputs start behaving normally.
4. Unplug monitor: remains good. Until reboot.WTF?
Raspberry Pi 4 Model B Rev 1.5, Debian GNU/Linux 12 (bookworm) 12.11. Two different Pis, same behavior.
https://jwz.org/b/yk2FLet's try a different question: How do I make a Pi4b Debian 12.11 believe that an HDMI monitor is connected even if one is not?
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Let's try a different question: How do I make a Pi4b Debian 12.11 believe that an HDMI monitor is connected even if one is not?
@jwz
I think there are HDMI deadplugs. Stupid solution, but maybe the easiest. -
@jwz
I think there are HDMI deadplugs. Stupid solution, but maybe the easiest.@neopostmodern I have used those for other purposes but of course they're full-sized HDMI so now I have to have one at the end of a dangling cable too, which is a pain in the ass.
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Let's try a different question: How do I make a Pi4b Debian 12.11 believe that an HDMI monitor is connected even if one is not?
The fact that things continue working *after I have unplugged the monitor* makes me think that this some kernel initialization or dependency nonsense and perhaps there's some modprobe that could fix it, but I didn't see a smoking gun in lsmod.
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Let's try a different question: How do I make a Pi4b Debian 12.11 believe that an HDMI monitor is connected even if one is not?
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Let's try a different question: How do I make a Pi4b Debian 12.11 believe that an HDMI monitor is connected even if one is not?
@jwz@mastodon.social There is fake monitor dongle that you can buy for a few dollars from China.
Example (untested): https://www.aliexpress.com/item/1005007634237816.html -
@jwz@mastodon.social There is fake monitor dongle that you can buy for a few dollars from China.
Example (untested): https://www.aliexpress.com/item/1005007634237816.htmlHEY EVERYBODY I HAVE BEEN INFORMED THAT FAKE HDID DONGLES EXIST. SIX TIMES.
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HEY EVERYBODY I HAVE BEEN INFORMED THAT FAKE HDID DONGLES EXIST. SIX TIMES.
@jwz@mastodon.social And I can't see any of the other posts about fake HDMI dongles. The wonders of federated network in action
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@jwz@mastodon.social And I can't see any of the other posts about fake HDMI dongles. The wonders of federated network in action
@bunny Wasn't "Fetch All Replies" supposed to have fixed that last year? https://blog.joinmastodon.org/2025/10/mastodon-4-5-for-devs/
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@bunny Wasn't "Fetch All Replies" supposed to have fixed that last year? https://blog.joinmastodon.org/2025/10/mastodon-4-5-for-devs/
@jwz@mastodon.social For people that use Mastodon I suppose
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