vc4-fkms-v3d locks up when connected to particular TV

[motadol]

Summary: On my Raspberry Pi 4B, the vc4-fkms-v3d driver appears to cause the system to lock up when HDMI is connected to a particular model of TV. Let's call this the Sony TV. (Lock up == no network, no video.) When I unplug the monitor, it resumes. Other TVs/monitors work fine. For this particular TV, I can get it to display video by booting headless, using `tvservice -o`, connecting the TV, using `tvservice -e "CEA 5 HDMI"`, then `fbset -depth 16`. But then it locks up when changing modes.

Any help would be appreciated. I'm happy to provide more info - just let me know what commands to run. Thanks in advance!

Symptoms:

• If I boot with the Sony TV connected:
  • I see the rainbow screen and the initial kernel messages.
  • At the point when the framebuffer gets reset, the screen goes blank and never returns. The machine is unresponsive and I cannot connect via SSH, even after waiting for 15 minutes. I believe this corresponds to the `switching to vc4drmfb from simple` line in `journalctl`.
  • Once I unplug the HDMI cable, I can then SSH soon after.
  • As long as the cable is unplugged, SSH is responsive.
  • If I plug in the HDMI cable again, SSH immediately stops working. I don't get disconnected; just no echo back of types keys.
  • Once I unplug the HDMI cable, SSH immediately resumes. All of my typed keys immediately appear.
  • If I plug in another TV or monitor after it has started up, it works fine.
• If I boot headless or with a different monitor, everything works fine. It boots up normally.
  • However, I get the same issue as above if I unplug the "good" TV/monitor and then plug in the Sony TV: everything immediately freezes and I cannot SSH. Once I disconnect the Sony TV, it's working again.
• If I boot with the Sony TV connected and `dtoverlay=vc4-fkms-v3d` commented out, it boots fine, but then I can't use emulationstation.
• Modifying or removing `hdmi_force_hotplug`, `hdmi_group`, and/or `hdmi_mode` does not help.
• If I boot with Lakka and the Sony TV, I get no video at all. (Other monitor or TV works fine.)
• I can get the Sony TV to work in a limited fashion as follows:
  • Boot headless.
  • Connect via SSH.
  • Run `tvservice -o`.
  • Connect the Sony TV.
  • Run `tvservice -e "CEA 5 HDMI"`. Screen is still blank (known issue), but the mode changes on the TV. Other modes work, too.
  • Run `fbset -depth 16`. Video now works.
  • Emulationstation + snes9x works, too. It even successfully changed mode to 640x480.
  • However, upon exiting snes9x, it locked up again. Disconnecting the Sony TV fixed it.
  • When I SSH'd in and ran `tvservice -s`, it said it was running in 1080p (not 1080i). Perhaps this is helpful for debugging?

System info:

• Hardware: Raspberry Pi 4B rev 1.2
• OS: Raspberry Pi OS Lite Buster, fully updated via apt. (Same on Lakka, see below.)
• Kernel: 4.19.118-v7l+
• TV: Sony KDL-40S2010, which only supports 1080i
• HDMI Port: 0 (next to USB-C)
• Power supply: Vilros Pi 4 USB-C Power Supply With Switch [3 Amp]
• /boot/config.txt:

  Code: Select all

  hdmi_force_hotplug=1
  hdmi_group=1
  hdmi_mode=5
  dtparam=audio=on
  [pi4]
  dtoverlay=vc4-fkms-v3d
  max_framebuffers=2
  [all]
  

• /boot/cmdline.txt (default)

  Code: Select all

  console=serial0,115200 console=tty1 root=PARTUUID=29feba32-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

• EDID dump:

  Code: Select all

  00ffffffffffff004dd900950101010129100103804628780a0dc9a05747
  982712484c20000001010101010101010101010101010101011d8018711c
  1620582c2500dfa42100009e8c0ad08a20e02d10103e960030a421000018
  000000fc00534f4e592054560a2020202020000000fd003a3e0f2e08000a
  202020202020013102031b76478502030406070123090707830100006603
  0c00100080011d007251d01e206e285500dfa42100001e8c0aa01451f016
  00267c430030a4210000988c0ad08a20e02d10103e9600dfa4210000188c
  0aa01451f01600267c4300dfa42100009800000000000000000000000000
  00000000000000000000000000000086
  

[cleverca22]

are there any errors or warnings in `dmesg`?
have you tried looking at the kernel logs over the serial port?

[kerry_s]

according ti this:
https://www.manualslib.com/manual/32102 ... s2010.html

the display is a 1366x768, which for the raspberry pi os leaves you with a blank screen bug.

search the forum for the fix/settings for config.txt

[motadol]

according ti this:
https://www.manualslib.com/manual/32102 ... s2010.html

the display is a 1366x768, which for the raspberry pi os leaves you with a blank screen bug.

search the forum for the fix/settings for config.txt

Doh! I had no idea. Switching to 720p solved the problem for me:

Code: Select all

hdmi_group=1
hdmi_mode=4

I can't get 1366x768 to work, but 720p is good enough for now. Thanks for the help!

That said, it still seems that there is a bug in vc4-fkms-v3d that causes the whole machine to lock up if I use 1080i mode with this TV. Having a blank screen is expected; a complete machine lockup is not. I haven't seen that reported anywhere else. Where is best to report that bug?

[kerry_s]

it's the tv, not the pi that's at fault here. my guess is there doing weird stuff for that resolution, which is something that only showed on laptops & only started appearing on tv's.

ya just have to get the numbers right, it works at 1366x768 once you put the right numbers in & select it in the gui.
example: i use 1600x900 resolution on a 1920x1080 display, but they don't have that on the list.
so i add this to config.txt:

Code: Select all

hdmi_group=2
hdmi_mode=83

then it's in the list & i can select it.

[kerry_s]

this is the settings:

Code: Select all

hdmi_group=2
hdmi_cvt=1366 768 60
hdmi_mode=87