Hi,
I am testing a recently bought "HDMI 7" 800x480 Display Backpack - Without Touch" module.
After connecting it to the raspberry pi and editing the config.txt file (as mentioned here: https://learn.adafruit.com/adafruit-5-8 ... -pi-config), it works fine. However, the EDID information is invalid. See the results of the following commands:
$: tvservice -d edid
Writtten 256 bytes to edid
$: od -t x1 edid
0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
*
0000400
$: edidparser edid
Enabling fuzzy format match...
Parsing edid...
HDMI: bad EDID header ff ff ff ff ff ff ff ff
edidparser exited with code -1
When the display is connected to a dell laptop, nothing shows up and the EDID information is not valid either.
See "dmesg" output after connecting the display to the laptop.
When the display is connected to a Jetson nano dev board, the screen is either white or shows the desktop environment but with flickering horizontal lines. The kernel (L4t 32.5) can't read the EDID as well, and uses a fallback edid.
See "dmesg" output after connecting the display to the nano.
The goal is to get it working on the nano. Could you confirm that the EDID EEPROM was not flashed correctly?
I also tested multiple HDMI cables.
If you need extra debug information, I am available.
Thank you.
HDMI 7" 800x480 Display Backpack - Without Touch - No EDID
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- hasan__
- Posts: 2
- Joined: Tue Jan 26, 2021 11:11 am
- adafruit_support_carter
- Posts: 29150
- Joined: Tue Nov 29, 2016 2:45 pm
Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED
To rule out it being something with that linux utility, can you try using it with some other video source - like another PC.
- hasan__
- Posts: 2
- Joined: Tue Jan 26, 2021 11:11 am
Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED
When connected to a different PC, the screen works, but 'xrandr --verbose' doesn't show the EDID as well.
Here is "dmesg" output when booting with the display connected to the PC. Same message shows up when connected after boot.
Here is "dmesg" output when booting with the display connected to the PC. Same message shows up when connected after boot.
- adafruit2
- Posts: 22144
- Joined: Fri Mar 11, 2005 7:36 pm
Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED
it could be you got a blank one, do you want the EDID info to write?
Code: Select all
0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x04, 0x81, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00,
0x01, 0x11, 0x01, 0x03, 0x80, 0x0F, 0x0A, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x80, 0x0C, 0x20, 0x80, 0x30, 0xE0, 0x2D, 0x10, 0x28, 0x30,
0xD3, 0x00, 0x6C, 0x44, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17,
- cesvar_
- Posts: 5
- Joined: Thu Sep 09, 2021 1:58 pm
Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED
Hi I'm having the same issue at hasan__
I'm able to use the 7" display just fine on an RPi4 using the config settings int he Adafruit guide, but when I used the Nvidia Jetson Nano I only get a blank screen. When using two displays to verify that the Jetson is displaying output properly it does register that there is a second display, but confusingly it reads it as a 40" screen rather than a 7"...
I'll note that when I used the 7" display during set up, it worked just fine, it was only after set up was complete and I was taken to the home Desktop that the display started to have issues.
I'm not too well versed with these devices, so I'm not too sure how to even approach trouble shooting. Would appreciate any info people might have on troubleshooting.
I'm able to use the 7" display just fine on an RPi4 using the config settings int he Adafruit guide, but when I used the Nvidia Jetson Nano I only get a blank screen. When using two displays to verify that the Jetson is displaying output properly it does register that there is a second display, but confusingly it reads it as a 40" screen rather than a 7"...
I'll note that when I used the 7" display during set up, it worked just fine, it was only after set up was complete and I was taken to the home Desktop that the display started to have issues.
I'm not too well versed with these devices, so I'm not too sure how to even approach trouble shooting. Would appreciate any info people might have on troubleshooting.
- adafruit2
- Posts: 22144
- Joined: Fri Mar 11, 2005 7:36 pm
Re: HDMI 7" 800x480 Display Backpack - Without Touch - No ED
does it work on your windows or mac computer?
Please be positive and constructive with your questions and comments.