aBUGSworstnightmare
Posts: 6399
Joined: Tue Jun 30, 2015 1:35 pm

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Thu Dec 08, 2022 6:00 am

run VNC server on your Pi and VNC Viewer on another device in the network. As long as X get's started you will be able to 'see' the desktop of the Pi biggern than on your small displays.
You don't want to build your own head-mounted display out of them? Might be simpler to buy one of the shelf (which has exactly said displays).

ManuZazen
Posts: 25
Joined: Thu Dec 01, 2022 2:26 pm

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Thu Dec 08, 2022 8:08 am

The goal is other than to build a head-mounted display, I can't tell more.

aBUGSworstnightmare
Posts: 6399
Joined: Tue Jun 30, 2015 1:35 pm

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Thu Dec 08, 2022 8:55 am

ManuZazen wrote:
Thu Dec 08, 2022 8:08 am
The goal is other than to build a head-mounted display, I can't tell more.
is that a commercial development?
Sorry, but I (aBUGSworstnightmare) don't offer FOC consulting for businesses! You've had yoir fair ammount of FOC support by me ...

Edit - in case you don't know: this is a users forum! Most 'people' here are Pi users - same as you - as you can see from nicknames shown in red.
If you get a replay from a 'green nicknamed' user then you are speakimg to an admin/RPT member.
Last edited by aBUGSworstnightmare on Fri Dec 09, 2022 9:04 am, edited 4 times in total.

ManuZazen
Posts: 25
Joined: Thu Dec 01, 2022 2:26 pm

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Fri Dec 09, 2022 8:21 am

I'm sorry I was not aware of this fact. So what is the link to raspberry support then ? I still haven't found it yet.

aBUGSworstnightmare
Posts: 6399
Joined: Tue Jun 30, 2015 1:35 pm

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Fri Dec 09, 2022 8:56 am

ManuZazen wrote:
Fri Dec 09, 2022 8:21 am
I'm sorry I was not aware of this fact. So what is the link to raspberry support then ? I still haven't found it yet.
your problem isn't the Pi - as said a few times - your problem is the display interface (that blue PCB which converts HDMI into MIPI) board,

You should ask the manufacturer of that board to support, not RPT.
From my postings above you can see evidence that the Pi is able to output the target resolution.

6by9
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 13795
Joined: Wed Dec 04, 2013 11:27 am
Location: ZZ9 Plural Z Alpha, aka just outside Cambridge.

Re: 2800x1440 display at 60Hz on the new Raspi4 2G

Fri Dec 09, 2022 2:54 pm

Having had a very quick look at the EDID decode, for some daft reason it repeats exactly the same resolution in all 6 detailed timing descriptors:

Code: Select all

  Detailed Timing Descriptors:
    DTD 1:  2880x1440   59.999051 Hz   2:1     87.359 kHz    257.970000 MHz (90 mm x 160 mm)
                 Hfront   50 Hsync   8 Hback   15 Hpol N
                 Vfront    8 Vsync   2 Vback    6 Vpol N
Due to the way the Pi display pipeline works, it can not handle odd values in the horizontal timings, so the back porch of 15 will cause the mode to be rejected (all 6 times). For normal displays this is only an issue with the 1366x768 (which is a bit of a weird one anyway as 1366 is not a multiple of 8).
The display lists no other resolutions.

I've modified the EDID to set the HBP to 16 instead of 15. Copy the following and save it as something like edid.txt.

Code: Select all

00ffffffffffff003354010000000000
0c1b0103800000780a07f59a564e8626
1e505400000000000000000000000000
000000000000c564404ab0a010503208
82005aa000000018000000fc00596f6e
6758696e672020202020000000ff0030
303030303030302020202020000000fd
00174b0ff022000a202020202020013f
02031774470000000000000023097f07
66030c00300080c564404ab0a0105032
0882005aa000000018c564404ab0a010
50320882005aa000000018c564404ab0
a01050320882005aa000000018c56440
49b0a01050320882005aa000000018c5
64404ab0a01050320882005aa0000000
1800000000000000000000000000005e
Run

Code: Select all

xxd -p -c 16 -r edid.txt  > edid.bin
to convert it from text to binary.

Code: Select all

sudo cp edid.bin /lib/firmware
to copy it into the appropriate system directory.

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sudo nano /boot/cmdline.txt
and add to the start of the line

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drm.edid_firmware=HDMI-A-1:edid.bin
do NOT add any carriage returns (the file must be just one line).

Reboot.
All being well the system should have ignored the EDID advertised by the display and used the file for HDMI-1 (the port closest to the USB-C power connector).
Software Engineer at Raspberry Pi Ltd. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.

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