Bluetooth PAN not working on PI 3B+ and 4B works on 3B

[carpa5]

Describe the bug
PAN connection time out on PI 3B+ and 4B, but works on 3B using latest Buster

To reproduce
In Windows or Android connect to PAN, wait 60 seconds and try to SSH into PI. It will not work

Expected behaviour
Should be able to SSH into PI anytime after connecting to PAN and SSH session should not drop.

Actual behaviour
Connect to PAN wait 60 seconds and one will not be able to SSH to Pi. Now we have to connect to PAN again and SSH immediately into Pi. Once SSH session is made if we do not press any key for about 60 seconds the connection is dropped and PAN connection has to be made again. If we change putty setting "Connection", "Seconds between keepalives" from the default 60 to 10 connection will not drop.

System
System Information

Raspberry Pi 4 Model B Rev 1.1
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"

Raspberry Pi reference 2013-02-09 (armhf)
Generated using spindle, http://asbradbury.org/projects/spindle/, 1f91088, stage4-lxde-edu.qed

Linux pi4 4.19.75-v7l+ #1270 SMP Tue Sep 24 18:51:41 BST 2019 armv7l GNU/Linux
Revision : c03111
Serial : 1000000098bd5f91
Model : Raspberry Pi 4 Model B Rev 1.1
Throttled flag : throttled=0x0
Camera : supported=0 detected=0

Videocore information

Sep 24 2019 17:34:59
Copyright (c) 2012 Broadcom
version cd3add54955f8fa065b414d8fc07c525e7ddffc8 (clean) (release) (start_cd)

alloc failures: 0
compactions: 0
legacy block fails: 0

Filesystem information

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 14728124 1752140 12208112 13% /
devtmpfs 1991720 0 1991720 0% /dev
tmpfs 2025512 0 2025512 0% /dev/shm
tmpfs 2025512 17728 2007784 1% /run
tmpfs 5120 0 5120 0% /run/lock
tmpfs 2025512 0 2025512 0% /sys/fs/cgroup
none 81920 312 81608 1% /var/log
none 40960 0 40960 0% /tmp
/dev/mmcblk0p1 524000 54384 469616 11% /boot
tmpfs 405100 0 405100 0% /run/user/0

Filename Type Size Used Priority

Package version information

raspberrypi-ui-mods:
Installed: (none)
raspberrypi-sys-mods:
Installed: 20190730
openbox:
Installed: (none)
lxpanel:
Installed: (none)
pcmanfm:
Installed: (none)
rpd-plym-splash:
Installed: (none)

Networking Information

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet x.x.x.x netmask x.x.x.x broadcast x.x.x.x
ether m.m.m.m txqueuelen 1000 (Ethernet)
RX packets 17930 bytes 14771002 (14.0 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5385 bytes 548859 (535.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet x.x.x.x netmask x.x.x.x
loop txqueuelen 1000 (Local Loopback)
RX packets 8 bytes 400 (400.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 400 (400.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

pan0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet x.x.x.x netmask x.x.x.x broadcast x.x.x.x
ether m.m.m.m txqueuelen 1000 (Ethernet)
RX packets 284 bytes 49955 (48.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 53 bytes 8623 (8.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet x.x.x.x netmask x.x.x.x broadcast x.x.x.x
ether m.m.m.m txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 29 bytes 6724 (6.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

USB Information

/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M

config.txt

arm_freq=1500
audio_pwm_mode=514
config_hdmi_boost=5
core_freq=500
core_freq_min=200
disable_commandline_tags=2
disable_l2cache=1
display_hdmi_rotate=-1
display_lcd_rotate=-1
enable_gic=1
force_eeprom_read=1
force_pwm_open=1
framebuffer_depth=16
framebuffer_ignore_alpha=1
framebuffer_swap=1
gpu_freq=500
gpu_freq_min=500
init_uart_clock=0x2dc6c00
lcd_framerate=60
pause_burst_frames=1
program_serial_random=1
hdmi_force_cec_address:0=65535
hdmi_force_cec_address:1=65535
hdmi_pixel_freq_limit:0=0x11e1a300
hdmi_pixel_freq_limit:1=0x11e1a300
device_tree=-
hdmi_cvt:0=
hdmi_cvt:1=
hdmi_edid_filename:0=
hdmi_edid_filename:1=
hdmi_timings:0=
hdmi_timings:1=

cmdline.txt

coherent_pool=1M 8250.nr_uarts=0 cma=64M bcm2708_fb.fbwidth=0 bcm2708_fb.fbheight=0 bcm2708_fb.fbdepth=16 bcm2708_fb.fbswap=1 smsc95xx.macaddr=DC:A6:32:16:83:93 vc_mem.mem_base=0x3f000000 vc_mem.mem_size=0x3f600000 dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait consoleblank=0 ipv6.disable=1

• Which model of Raspberry Pi? e.g. Pi3B+, PiZeroW
  Problem occurs on PI3B+ and PI4B, but works on 3B

• Which OS and version (cat /etc/rpi-issue)?
  Raspberry Pi reference 2013-02-09 (armhf)
  Generated using spindle, http://asbradbury.org/projects/spindle/, 1f91088, stage4-lxde-edu.qed

• Which firmware version (vcgencmd version)?
  Sep 24 2019 17:34:59
  Copyright (c) 2012 Broadcom
  version cd3add54955f8fa065b414d8fc07c525e7ddffc8 (clean) (release) (start_cd)

• Which kernel version (uname -a)?
  Linux pi4 4.19.75-v7l+ solved issue of mirroring screen after rotation. #1270 SMP Tue Sep 24 18:51:41 BST 2019 armv7l GNU/Linux

Logs
Log of connecting to PAN and how it disconnects:

Oct 30 07:45:05 localhost bluetoothd[468]: bnep: bridge pan0: interface bnep0 added
Oct 30 07:45:05 localhost systemd-udevd[2500]: Using default interface naming scheme 'v240'.
Oct 30 07:45:05 localhost kernel: [ 1123.805457] pan0: port 1(bnep0) entered blocking state
Oct 30 07:45:05 localhost kernel: [ 1123.805471] pan0: port 1(bnep0) entered disabled state
Oct 30 07:45:05 localhost kernel: [ 1123.805823] device bnep0 entered promiscuous mode
Oct 30 07:45:05 localhost kernel: [ 1123.806693] pan0: port 1(bnep0) entered blocking state
Oct 30 07:45:05 localhost kernel: [ 1123.806706] pan0: port 1(bnep0) entered forwarding state
Oct 30 07:45:05 localhost systemd-udevd[2500]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Oct 30 07:45:05 localhost dhcpd[702]: DHCPREQUEST for 192.168.3.101 from 80:86:f2:dc:36:a0 via pan0
Oct 30 07:45:05 localhost dhcpd[702]: Wrote 1 leases to leases file.
Oct 30 07:45:05 localhost dhcpd[702]: DHCPACK on 192.168.3.101 to 80:86:f2:dc:36:a0 (richardp14s) via pan0
Oct 30 07:46:11 localhost kernel: [ 1190.186874] pan0: port 1(bnep0) entered disabled state
Oct 30 07:46:11 localhost kernel: [ 1190.187640] device bnep0 left promiscuous mode
Oct 30 07:46:11 localhost kernel: [ 1190.187657] pan0: port 1(bnep0) entered disabled state
Oct 30 07:46:13 localhost ntpd[1939]: Deleting interface #4 pan0, 192.168.3.1#123, interface stats: received=0, sent=0, dropped=0, active_time=471 secs

Additional context
Since this works on a 3B I thought it might be firmware related, so I replaced the "/lib/firmware" (I don't know which specific module is used for bluetooth) folder from the previous release:

Aug 15 2019 12:07:10
Copyright (c) 2012 Broadcom
version 0e6daa5106dd4164474616408e0dc24f997ffcf3 (clean) (release) (start_cd)

Then I rebooted and now the PAN does not disconnect anymore.

Any help would be appreciated.

[pelwell]

I think this is a duplicate/variation of RPi-Distro/firmware-nonfree#7, so please follow that thread (I'll ping you) and I'll close this one.