paulslocum
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Is hdmi_force_hotplug the same as manually turning on HDMI via tvservice?

Tue Apr 17, 2018 2:12 pm

Does hdmi_force_hotplug=1 do anything unique, or is it the effectively same as automatically turning on an HDMI mode using tvservice in rc.local?

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DougieLawson
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Re: Is hdmi_force_hotplug the same as manually turning on HDMI via tvservice?

Tue Apr 17, 2018 2:27 pm

hdmi_force_hotplug forces the GPU to enable the HDMI settings even when there's no HDMI device connected. You'll usually need to include hdmi_group=n & hdmi_mode=nn with some override settings for your HDMI device.
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paulslocum
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Re: Is hdmi_force_hotplug the same as manually turning on HDMI via tvservice?

Wed Apr 18, 2018 2:59 pm

Best I can tell, tvservice does the same thing. What I'm wondering is if there's any difference between the two technically, like does hdmi_force_hotplug set some bits on the HDMI port to improve compatibility, or is it only forcing the HDMI on (the same as turning on an explicit HDMI mode with tvservice)

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DougieLawson
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Re: Is hdmi_force_hotplug the same as manually turning on HDMI via tvservice?

Wed Apr 18, 2018 3:35 pm

The config.txt option is automatic at boot time. Most folks won't ever need it, 99.99% of HDMI display devices "just work" with a Raspberry with nothing special needed in /boot/config.txt or with the tvservice command.
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paulslocum
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Re: Is hdmi_force_hotplug the same as manually turning on HDMI via tvservice?

Wed Apr 18, 2018 9:00 pm

I hope so, but I find quite a few reports of the issue on the forums, and I didn't have to test many devices to find one that didn't work, so I think the issue may be more a bit more prevalent than that.

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