Hi
It looks like the video mode isn’t being used. So I am going to fix that and re-apply 1200p and 800p to the kernel. I will also patch Kodi to support these modes.
It looks like we might have to use reduced blanking for your monitor, as I am not sure it will handle a 193Mhz pixel clock, but I will first produce a kernel without this.
Sam
ok, even though i only understand a small percentage of what you are trying to tell me ( 
) your work is very much appreciated! big thank you for helping me, i really hope this is going to work out somehow …
have a nice day
bendsch
Try sudo apt-get update && sudo apt-get dist-upgrade now. I added support for 800p and 1200p resolutions.
hi sam
i tried again, with both resolutions (1220, 800) still no picture …
osmc@osmc:~$ cat /sys/class/amhdmitx/amhdmitx0/disp_cap
720p*
osmc@osmc:~$ echo 1200p | sudo tee /sys/class/display/mode
1200p
osmc@osmc:~$ echo 800p | sudo tee /sys/class/display/mode
800p
You need to upload some proper logs if we are to make some progress with this. Please verify your kernel version with uname.
Please check the disp_cap value, the output in journalctl again, etc
I made a lot of significant changes to try and get this working for you, but just saying it doesn’t work does not give me clues on how to progress further.
ok, yes - you are absolutely right. i am on the road right now, but i will provide the logs tomorrow morning.
in the meantime: thanks for you effort
Hi Sam,
I am sorry it took so long, but here finally are my logs:
osmc@osmc:~$ sudo -s
root@osmc:/home/osmc# systemctl stop mediacenter
root@osmc:/home/osmc# echo “1200p” > /sys/class/display/mode
root@osmc:/home/osmc# cat /sys/class/display/mode
1200p
root@osmc:/home/osmc# journalctl | paste-log
http://paste.osmc.io/quseweyusa
do you need anything else?
Bendsch
Hi
Thanks for the logs. We also added 800p support, and I think that the Cinema Display that you have should support this resolution.
Unfortunately the log you provided doesn’t provide any clues because the log is full of CEC errors (Cinema Display doesn’t do CEC). dmesg | paste-log may be a better choice.
Does the Cinema Display just say no signal? I would like to see disp_cap again to see if the kernel now picks up the Cinema Display’s preferred mode and tries to set that up by default.
Thanks
Sam
unforunately the cinema display does not have a status message on its screen like other displays if no device is connected, so i cant tell.
here are the logs:
osmc@osmc:~$ dmesg | paste-log
http://paste.osmc.io/upazejiran
osmc@osmc:~$ cat /sys/class/amhdmitx/amhdmitx0/disp_cap
720p*
osmc@osmc:~$ cat /sys/class/amhdmitx/amhdmitx0/hpd_state
1
Did you update the kernel? Should read as 3.10.102-5.
Sam
yes apparently i did …
osmc@osmc:~$ uname -a
Linux osmc 3.10.102-5-osmc #1 SMP Wed Jul 27 17:27:46 UTC 2016 armv7l GNU/Linux
I am not sure of a solution to this. If you have also tried 800p and disp_cap isn’t showing the new modes, then I can only suspect the adapter.
i found this: Apple's 27" iMac only supports native or 720p video input, no 1080p | AppleInsider
the part at the bottom under “EDID limitation” seems interesting.
It appears the 27" iMac could accept 1080p input, and certainly can support display of the video resolution, as it falls well within its 2560x1440 native resolution. A similar problem affects Apple’s 24" LED Cinema Display, which has a native 1920x1200 resolution but only supports that resolution via its DisplayPort input; like the 27" iMac, it won’t accept a 1080p signal (1920x1080), the common format of higher end HD equipment such as HDMI set top boxes and the PS3, even though it appears it should be able to.
does that mean the pi simply scales the picture o 720? and if yes is it possible to do that on the vero too?
another interesting discussion on this topic is here: EDID from large (> 1920 x 1200) displays - Raspberry Pi Forums
“There are two variants of 1920x1200@60, one with reduced blanking and one with normal blanking. Raspberry Pi can only drive the former. However, the modified EDID listed the reduced blanking version of the format as the preferred resolution and that’s what the pi is trying to drive. If the monitor does not support the reduced blanking version (or 1920x1200 in general, as stated on Kanex’s page), then it is Kanex responsibility to present the correct EDID to the pi. I am waiting for a response from Apple regarding the original EDID of the display.”
yes i tried that.
It’s possible that the display needs to be driven with a reduced blanking mode. I have made this change and I am now building a kernel with these changes for you. I’ll let you know when it’s ready.
The problem is that the adapter or the Cinema Display’s EDID isn’t stating that it wants a reduced blanking mode. This final kernel is the last solution I can really propose to driving this display. There seems to be some contradicting documentation about it. Without the Cinema Display showing us if it’s getting a signal, it’s also hard to tell if the signal we are generating is just out of range, or if there is some other issue.
Sam
hmm ok … i see that you cant spend more time on this topic, but isnt that the exact description of our problem?
EDID limitation
It appears the 27" iMac could accept 1080p input, and certainly can support display of the video resolution, as it falls well within its 2560x1440 native resolution. A similar problem affects Apple’s 24" LED Cinema Display, which has a native 1920x1200 resolution but only supports that resolution via its DisplayPort input; like the 27" iMac, it won’t accept a 1080p signal (1920x1080), the common format of higher end HD equipment such as HDMI set top boxes and the PS3, even though it appears it should be able to.
The problem is that Apple’s EDID (Extended Display Identification Data) on the iMac and LED Cinema Display doesn’t advertise 1080p as an option. EDID is a simple data structure a display sends to output devices that outlines what video formats and settings it knows how to support. Both devices appear capable of 1080p but simply don’t advertise that capability in a way that external devices like the AV360 and Kanex HD can take advantage of.
It appears Apple could update the firmware for these displays to enable support of 1080p input, allowing users to input full 1080p video from devices such as the PS3. Users might not notice a major difference, as experts say its hard to see a real difference between 720p and 1080p on screens smaller than 50 inches.
However, some devices are hardwired to only support 1080p, and can’t scale their output to support the Cinema Display’s slightly higher resolution nor the 27" iMacs much higher resolution, forcing them to downscale to 720p or not work at all (as is the case with the LED Cinema Display, which is really only indended to work with Apple’s Mini DisplayPort-equipped MacBooks and modern desktop Macs).
If the Cinema Display really is capable of 1080p, then echo ‘1080p’ to mode should get you a picture, but it doesn’t. It’s certainly obvious that the EDID that the monitor is sending is bogus.
I have also added modes for 1200p and 800p that should work but it doesn’t seem to be helping you.
The new kernel is now ready (sudo apt-get update && sudo apt-get dist-upgrade) should get it down. it might take an hour or so for the CDN to sync.
I have no problem spending time on the topic, the problem is that I am starting to reach a point where I’m not sure how to proceed, short of having one of these displays in front of me.
Sam
ok i understand. the last thing i can offer you is to ssh into my vero if that would help.
I won’t be able to look until this evening, but if you PM me your SSH details, I will take a look.
Thanks
Sam
ok lets do that, but first i will try the new kernel. thanx in the meantime once again.
just to clarify something: i think the 24" cinema display is not capable of displaying 1080p (but 1200p, 800p and 640p) , the 27" imac is …