[Asus PN42] PC Mode Issue

Quote from HansM

As of today, I *HAD* the same problem on my LG G4.

After a lot of experimenting I came to the conclusion some signal is telling the HDMI port of the TV to jump into PC mode. Even the GUI at 1920x1080@60 jumped into PC mode.

Then I tried @50: no PC mode. tried @30: no PC mode. So started the whitelist with only 3840x2160@30: Happy times, no more PC mode!

Added all the other modes one by one and tested. In my case, the 3840x2160@60 and [email protected] modes on the whitelist were the culprit. Should be the same for 1920x1080 but didn't tried that yet...

Good luck with this 'typical feature' of your LG OLED TV.

If you're outputting 24fps content in 30fps progressive don't expect hugely watchable results.

Quote from HansM

So is it some kind of miscommunication between LE and LG TV? Who can tell...

• make sure your HDMI cable is conform to HDMI 2.0 / 2.1 standard
• try other HDMI pots on your TV

Quote from HansM

So is it some kind of miscommunication between LE and LG TV?

It's a bug/feature of your TV's firmware. Maybe some setting in the service menu would disable PC mode.

On a Samsung TV the PC mode activates only when you change the "Device icon" to "PC".

My 65CX got new firmware a week or two ago, never had any problems with any of my 5 Pi4/5 with LE12/13, always on latest nightly, never had any problems with my Intels running LE Generic on that tv either.

Quote from HansM

Back to square one.

It seems that after every start of LE and LG TV, HDMI4 input is reset to PC.

After changing the icon of the HDMI4 port on the LG TV, or even change one character of the name of the HDMI4 port, the desired settings are available again. I don't have this issue with the set-top box of my Dutch ISP provider KPN connected to HDMI3.

So is it some kind of miscommunication between LE and LG TV? Who can tell...

This couldn't be as simple as RGB = PC, 4:2:2 YCbCr = Video could it? (Or infoframes flagging 0-255 = PC, 16-235 = Video levels?)

Is there a command line command you can run on a Pi 4B to report the HDMI output format being used - that might help add some information?

Some info from here:

$ grep -A9 HDMI-A-1 /sys/kernel/debug/dri/?/state
connector[33]: HDMI-A-1
    crtc=crtc-2
    self_refresh_aware=0
    max_requested_bpc=8
    colorspace=Default
    broadcast_rgb=Automatic
    is_limited_range=y
    output_bpc=8
    output_format=RGB
    tmds_char_rate=74250000
$ kmsprint -p | grep -A 14 HDMI-A-1
Connector 0 (33) HDMI-A-1 (connected)
   EDID (1) = blob-id 300 len 256 (immutable)
   DPMS (2) = 0 (On) [On=0|Standby=1|Suspend=2|Off=3]
   TILE (4) = blob-id 0 (immutable)
   link-status (5) = 0 (Good) [Good=0|Bad=1]
   non-desktop (6) = 0 [0 - 1] (immutable)
   HDR_OUTPUT_METADATA (7) = blob-id 0
   CRTC_ID (20) = object id 87
   max bpc (34) = 8 [8 - 12]
   left margin (35) = 0 [0 - 100]
   right margin (36) = 0 [0 - 100]
   top margin (37) = 0 [0 - 100]
   bottom margin (38) = 0 [0 - 100]
   Colorspace (39) = 0 (Default) [Default=0|SMPTE_170M_YCC=1|BT709_YCC=2|XVYCC_601=3|XVYCC_709=4|SYCC_601=5|opYCC_601=6|opRGB=7|BT2020_CYCC=8|BT2020_RGB=9|BT2020_YCC=10|DCI-P3_RGB_D65=11|DCI-P3_RGB_Theater=12]
   Broadcast RGB (40) = 0 (Automatic) [Automatic=0|Full=1|Limited 16:235=2

Quote from HansM

Thanks noggin, but I already tried 16-235 video levels in the settings. It doesn't matter.

More and more I think the problem is with LG OLED tv's and their detection methods of HDMI input signals.

As I mentioned earlier:

"It seems that after every start of LE and LG TV, HDMI4 input is reset to PC.

After changing the icon of the HDMI4 port on the LG TV, or even change one character of the name of the HDMI4 port, the desired settings are available again." -----> this is very strange imho...

smp is probably right and it is a bug in the LG firmware....

Thank you everyone!

Display More

What about RGB vs YCbCr (aka 4:4:4/4:2:2/4:2:0?)

Quote from popcornmix

Some info from here:

Code

$ grep -A9 HDMI-A-1 /sys/kernel/debug/dri/?/state
connector[33]: HDMI-A-1
    crtc=crtc-2
    self_refresh_aware=0
    max_requested_bpc=8
    colorspace=Default
    broadcast_rgb=Automatic
    is_limited_range=y
    output_bpc=8
    output_format=RGB
    tmds_char_rate=74250000
$ kmsprint -p | grep -A 14 HDMI-A-1
Connector 0 (33) HDMI-A-1 (connected)
   EDID (1) = blob-id 300 len 256 (immutable)
   DPMS (2) = 0 (On) [On=0|Standby=1|Suspend=2|Off=3]
   TILE (4) = blob-id 0 (immutable)
   link-status (5) = 0 (Good) [Good=0|Bad=1]
   non-desktop (6) = 0 [0 - 1] (immutable)
   HDR_OUTPUT_METADATA (7) = blob-id 0
   CRTC_ID (20) = object id 87
   max bpc (34) = 8 [8 - 12]
   left margin (35) = 0 [0 - 100]
   right margin (36) = 0 [0 - 100]
   top margin (37) = 0 [0 - 100]
   bottom margin (38) = 0 [0 - 100]
   Colorspace (39) = 0 (Default) [Default=0|SMPTE_170M_YCC=1|BT709_YCC=2|XVYCC_601=3|XVYCC_709=4|SYCC_601=5|opYCC_601=6|opRGB=7|BT2020_CYCC=8|BT2020_RGB=9|BT2020_YCC=10|DCI-P3_RGB_D65=11|DCI-P3_RGB_Theater=12]
   Broadcast RGB (40) = 0 (Automatic) [Automatic=0|Full=1|Limited 16:235=2

Display More

So RGB - is there a way to force 4:2:2 ? (I realise this will only work at 30Hz refresh and below on 2160p resolutions without a high-bandwidth 'Enhanced' HDMI path and destination)

It can't be as simple as LG interpreting RGB=PC and YCbCr=Video can it?

I have several different devices connected to my LG 65CX on all 4 HDMI including a switch with 4 devices (its 5 Pi4/5 and a couple of PC & a Shield Pro) and my tv never changes its settings by itself.