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<p>Trying to stay retired, but a fella can't never get totally away from the sea....</p>
<p>Needing to setup a PI 4B to simply display words for an Irish Pub Night to both the onboard HDMI outputs. One will go to a projector; the other to a 40" TV. Both HDMI. Both need to stay in Sync.</p>
<p>I'm testing it now on a pair of 1920x1080 HDMI monitors. Both work fine as independent monitors.</p>
<p>My notes on how to do this came from Bing AI, courtesy of Raspian Forums, and seemed pretty simple:</p>
<div><span>Y<strong><em>es, you can make both HDMI outputs on a Raspberry Pi 4 have the same output on Raspbian. Here are the steps:</em></strong></span></div>
<div><strong><em> </em></strong></div>
<div><strong><em>Use the xrandr command to mirror the displays1. Replace <projector> and <desktop> with your display names:</em></strong></div>
<div><strong><em>xrandr --output <projector> --same-as <desktop></em></strong></div>
<div><strong><em>In the example provided in the forum, <projector> was HDMI-2, and <desktop> was HDMI-11.</em></strong></div>
<div><strong><em>To check the display names, run the following command when both displays are attached1:</em></strong></div>
<div><strong><em>xrandr --current</em></strong></div>
<div><strong><em> </em></strong></div>
<div><strong><em>Please note that these steps should work by default on Raspberry Pi OS, Bullseye2. If you encounter any issues, please let me know! I’m here to help.</em></strong></div>
<p><br /></p>
<p>Alas, it ain't working.</p>
<p>eal@raspberrypi:~ $ xrandr<br />Screen 0: minimum 16 x 16, current 3840 x 1080, maximum 32767 x 32767<br />XWAYLAND0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm<br /> 1920x1080 59.96*+<br /> 1440x1080 59.99 <br /> 1400x1050 59.98 <br /> 1280x1024 59.89 <br /> 1280x960 59.94 <br /> 1152x864 59.96 <br /> 1024x768 59.92 <br /> 800x600 59.86 <br /> 640x480 59.38 <br /> 320x240 59.52 <br /> 1680x1050 59.95 <br /> 1440x900 59.89 <br /> 1280x800 59.81 <br /> 720x480 59.71 <br /> 640x400 59.95 <br /> 320x200 58.96 <br /> 1600x900 59.95 <br /> 1368x768 59.88 <br /> 1280x720 59.86 <br /> 1024x576 59.90 <br /> 864x486 59.92 <br /> 720x400 59.55 <br /> 640x350 59.77 <br />XWAYLAND1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 520mm x 290mm<br /> 1920x1080 59.96*+<br /> 1440x1080 59.99 <br /> 1400x1050 59.98 <br /> 1280x1024 59.89 <br /> 1280x960 59.94 <br /> 1152x864 59.96 <br /> 1024x768 59.92 <br /> 800x600 59.86 <br /> 640x480 59.38 <br /> 320x240 59.52 <br /> 1680x1050 59.95 <br /> 1440x900 59.89 <br /> 1280x800 59.81 <br /> 720x480 59.71 <br /> 640x400 59.95 <br /> 320x200 58.96 <br /> 1600x900 59.95 <br /> 1368x768 59.88 <br /> 1280x720 59.86 <br /> 1024x576 59.90 <br /> 864x486 59.92 <br /> 720x400 59.55 <br /> 640x350 59.77 <br />neal@raspberrypi:~ $ xrandr --listmonitors<br />Monitors: 2<br /> 0: +XWAYLAND0 1920/510x1080/290+0+0 XWAYLAND0<br /> 1: +XWAYLAND1 1920/520x1080/290+1920+0 XWAYLAND1<br />neal@raspberrypi:~ $ xrandr --output 1 --same-as 0<br />warning: output 1 not found; ignoring<br />neal@raspberrypi:~ $ Xrandr<br />bash: Xrandr: command not found<br />neal@raspberrypi:~ $ xrandr --output XWAYLAND1 --same-as XWAYLAND0<br />X Error of failed request: BadMatch (invalid parameter attributes)<br /> Major opcode of failed request: 139 (RANDR)<br /> Minor opcode of failed request: 7 (RRSetScreenSize)<br /> Serial number of failed request: 29<br /> Current serial number in output stream: 30<br />neal@raspberrypi:~ $ xrandr --output +XWAYLAND1 --same-as +XWAYLAND0<br />warning: output +XWAYLAND1 not found; ignoring</p>
<p>The Screen Layout Editor shows displays as HDMI-A-1 and HDMI-A-2, so I also tried...</p>
<p>neal@raspberrypi:~ $ xrandr --output HDMI-A-2 --same-as HDMI-A-1<br />warning: output HDMI-A-2 not found; ignoring<br />neal@raspberrypi:~ $ xrandr --output HDMI-2 --same-as HDMI-1<br />warning: output HDMI-2 not found; ignoring</p>
<p>I don't see an option in xrandr to simply tell me what outputs it thinks it has. </p>
<p>And, is there a better way of doing this? Also considering that the real use will involve beer, and the projector may have different resolution from the TV?</p>
<p>regards,</p>
<p>Neal</p>
<p><br /></p>
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