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<p>A quick epilogue: Apparently the most recent Raspian image comes with this WayLand graphical interface in place of the more traditional X. </p>
<p>And apparently Wayland breaks a whole lot of china, </p>
<p>There is an option in raspi-config to revert back to X, and at that point xrandr stuff "just works". </p>
<p id="reply-intro">On 2024-01-01 20:18, Neal Rhodes via Ale wrote:</p>
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<p>Thanks for the reply. Fair enough on resolution. Frankly, VGA resolution would be fine. We're putting up big words.</p>
<p>I plugged in the 2nd monitor again after dinner, and the xrandr --current now reports the 2nd HDMI as XWAYLAND2, not XWAYLAND1. </p>
<p>I tried your suggestion regarding using the Screen Layout Editor, and indeed one can position the 2nd HDMI on top of the 1st. Then what happens is IF you move a window on the first screen, it shows up on both. UNTIL you let go of the mouse button, when it disappears.</p>
<p>I did get the xrandr --output XWAYLAND2 --same-as XWAYLAND0 to run to completion with out errors, and got the same behavior.</p>
<p>Rebooted, and the 2nd HDMI was back to XWAYLAND1. </p>
<p>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</p>
<p>This says to me that the syntax was ok, and it passed the initial edits, and tried to make that action. </p>
<p>As you note, these are nearly identical displays. The only difference I spot is 0 has 510mm, and 1 has 520mm. </p>
<p>I did find some pretty dense discussion of mirroring displays of different resolution: <a href="https://www.baeldung.com/linux/mirror-monitors-different-resolutions" target="_blank" rel="noopener noreferrer">https://www.baeldung.com/linux/mirror-monitors-different-resolutions</a> but it's waaaaaaay to late in the day to try and parse that, especially with light grey print on white.</p>
<p>As you note, a splitter might be less of a headache than this, which i sure thought would be simple.</p>
<p id="v1v1reply-intro">On 2024-01-01 16:25, Alex Carver via Ale wrote:</p>
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<div class="v1v1pre">Answering in reverse, if your projector and TV will have different resolutions then nothing is going to save you short of just making the Pi display at the lowest resolution of the two devices.<br /><br />Simplest solution is an actual HDMI splitter and then you don't have to think about it.<br /><br />But you can run this to get the current displays:<br />xrandr --current<br /><br />Some posts suggest you can use the graphical screen setup tool (Screen Layout Editor) to overlap the monitors which will result in sharing content. Drag one monitor over the top of the other.<br /><br /><br />On 2024-01-01 12:48, Neal Rhodes via Ale wrote:
<blockquote style="padding: 0 0.4em; border-left: #1010ff 2px solid; margin: 0;"><br /><br />Trying to stay retired, but a fella can't never get totally away from the sea....<br /><br />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.<br /><br />I'm testing it now on a pair of 1920x1080 HDMI monitors. Both work fine as independent monitors.<br /><br />My notes on how to do this came from Bing AI, courtesy of Raspian Forums, and seemed pretty simple:<br /><br />Y_es, you can make both HDMI outputs on a Raspberry Pi 4 have the same output on Raspbian. Here are the steps:_<br />_ _<br />_Use the xrandr command to mirror the displays1. Replace <projector> and <desktop> with your display names:_<br />_xrandr --output <projector> --same-as <desktop>_<br />_In the example provided in the forum, <projector> was HDMI-2, and <desktop> was HDMI-11._<br />_To check the display names, run the following command when both displays are attached1:_<br />_xrandr --current_<br />_ _<br />_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._<br /><br />Alas, it ain't working.<br /><br />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<br /><br />The Screen Layout Editor shows displays as HDMI-A-1 and HDMI-A-2, so I also tried...<br /><br />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<br /><br />I don't see an option in xrandr to simply tell me what outputs it thinks it has.<br /><br />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?<br /><br />regards,<br /><br />Neal<br /><br />_______________________________________________<br />Ale mailing list<br /><a href="mailto:Ale@ale.org" rel="noreferrer">Ale@ale.org</a><br /><a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank" rel="noopener noreferrer">https://mail.ale.org/mailman/listinfo/ale</a><br />See JOBS, ANNOUNCE and SCHOOLS lists at<br /><a href="http://mail.ale.org/mailman/listinfo" target="_blank" rel="noopener noreferrer">http://mail.ale.org/mailman/listinfo</a></blockquote>
<br />_______________________________________________<br />Ale mailing list<br /><a href="mailto:Ale@ale.org" rel="noreferrer">Ale@ale.org</a><br /><a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank" rel="noopener noreferrer">https://mail.ale.org/mailman/listinfo/ale</a><br />See JOBS, ANNOUNCE and SCHOOLS lists at<br /><a href="http://mail.ale.org/mailman/listinfo" target="_blank" rel="noopener noreferrer">http://mail.ale.org/mailman/listinfo</a></div>
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<div class="pre" style="margin: 0; padding: 0; font-family: monospace">_______________________________________________<br />Ale mailing list<br /><a href="mailto:Ale@ale.org">Ale@ale.org</a><br /><a href="https://mail.ale.org/mailman/listinfo/ale" target="_blank" rel="noopener noreferrer">https://mail.ale.org/mailman/listinfo/ale</a><br />See JOBS, ANNOUNCE and SCHOOLS lists at<br /><a href="http://mail.ale.org/mailman/listinfo" target="_blank" rel="noopener noreferrer">http://mail.ale.org/mailman/listinfo</a></div>
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