Raspi4/Buster USB-TV-stick causes endless errors

Start by reproducing the Terratec H6 behavior on Raspberry Pi 3B+/Stretch and Pi 4/Buster, comparing the supplied dmesg output from the em28xx and drxk paths. Trace the repeated I2C errors while TV playback is active; done means playback no longer produces the endless errors, with the relevant regression covered by an appropriate kernel test or reproducible verification.

i have a problem with the Terratec H6 (identified as Terratec H5 MKii) - Driver: dvb-usb-terratec-h5-drxk.fw.

I have 2 Raspis (Raspi3b+/Stretch) and Raspi4-4GB/Buster.
Problem is the different handling of the driver for the USB-TV stick (Terratec H6 or
H5MkII ).

With stretch/Leia 18.2/Raspi3b+ no errors
With buster/Leia 18.6/Raspi4 4GB always and never ending errors when TV playing

Below see dmesg when I connect the stick to the different Raspis:

Raspberry Pi 3B+
Raspbian Stretch (Kernel: Linux 4.19.66-v7+)
Kodi Leia 18.2 Git:20190428-a94ccc8ba5 - compiled 2019-04-30
Driver dvb-usb-terratec-h5-drxk.fw.

[ 327.813566] usb 1-1.3.3: new high-speed USB device number 21 using dwc_otg
[ 327.945084] usb 1-1.3.3: New USB device found, idVendor=0ccd, idProduct=10b2, bcdDevice= 1.00
[ 327.945095] usb 1-1.3.3: New USB device strings: Mfr=3, Product=1, SerialNumber=2
[ 327.945100] usb 1-1.3.3: Product: TERRATCE H5 MKII
[ 327.945105] usb 1-1.3.3: Manufacturer: TERRATEC
[ 327.945110] usb 1-1.3.3: SerialNumber: 123456789ABCD
[ 327.945878] em28xx 1-1.3.3:1.0: New device TERRATEC TERRATCE H5 MKII @ 480 Mbps (0ccd:10b2, interface 0, class 0)
[ 327.945889] em28xx 1-1.3.3:1.0: Audio interface 0 found (Vendor Class)
[ 327.945895] em28xx 1-1.3.3:1.0: Video interface 0 found: isoc
[ 327.945900] em28xx 1-1.3.3:1.0: DVB interface 0 found: isoc
[ 328.013804] em28xx 1-1.3.3:1.0: chip ID is em2884
[ 328.090977] em28xx 1-1.3.3:1.0: EEPROM ID = 26 00 00 00, EEPROM hash = 0xbcd5a8cf
[ 328.090986] em28xx 1-1.3.3:1.0: EEPROM info:
[ 328.090991] em28xx 1-1.3.3:1.0: microcode start address = 0x0004, boot configuration = 0x00
[ 328.097948] em28xx 1-1.3.3:1.0: I2S audio, 5 sample rates
[ 328.097958] em28xx 1-1.3.3:1.0: 500mA max power
[ 328.097972] em28xx 1-1.3.3:1.0: Table at offset 0x27, strings=0x2298, 0x1c6a, 0x1286
[ 328.163517] em28xx 1-1.3.3:1.0: Identified as Terratec Cinergy H6 rev. 2 (card=101)
[ 328.163534] em28xx 1-1.3.3:1.0: Currently, V4L2 is not supported on this model
[ 328.163541] em28xx 1-1.3.3:1.0: dvb set to isoc mode.
[ 328.163719] em28xx 1-1.3.3:1.0: Binding audio extension
[ 328.163724] em28xx 1-1.3.3:1.0: em28xx-audio.c: Copyright (C) 2006 Markus Rechberger
[ 328.163729] em28xx 1-1.3.3:1.0: em28xx-audio.c: Copyright (C) 2007-2016 Mauro Carvalho Chehab
[ 328.163839] em28xx 1-1.3.3:1.0: Endpoint 0x83 high-speed on intf 0 alt 7 interval = 8, size 196
[ 328.163846] em28xx 1-1.3.3:1.0: Number of URBs: 1, with 64 packets and 192 size
[ 328.169691] em28xx 1-1.3.3:1.0: Audio extension successfully initialized
[ 328.169708] em28xx 1-1.3.3:1.0: Binding DVB extension
[ 328.263488] usb 1-1.3.4: new high-speed USB device number 22 using dwc_otg
[ 328.400889] usb 1-1.3.4: New USB device found, idVendor=0461, idProduct=037b, bcdDevice= 1.01
[ 328.400902] usb 1-1.3.4: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ 328.400907] usb 1-1.3.4: Product: USB Scanner
[ 328.750619] drxk: status = 0x439260d9
[ 328.750642] drxk: detected a drx-3926k, spin A2, xtal 20.250 MHz
[ 332.766944] drxk: DRXK driver version 0.9.4300
[ 332.796015] drxk: frontend initialized.
[ 332.796054] tda18271 4-0060: creating new instance
[ 332.797813] tda18271: TDA18271HD/C2 detected @ 4-0060
[ 333.254709] dvbdev: DVB: registering new adapter (1-1.3.3:1.0)
[ 333.254739] em28xx 1-1.3.3:1.0: DVB: registering adapter 0 frontend 0 (DRXK DVB-C DVB-T)...
[ 333.257065] em28xx 1-1.3.3:1.0: DVB extension successfully initialized
[ 333.257087] em28xx 1-1.3.3:1.0: Registering input extension
[ 333.257479] Registered IR keymap rc-nec-terratec-cinergy-xs
[ 333.258173] rc rc0: 1-1.3.3:1.0 IR as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/rc/rc0
[ 333.258538] input: 1-1.3.3:1.0 IR as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/rc/rc0/input6
[ 333.259012] rc rc0: lirc_dev: driver em28xx registered at minor = 0, scancode receiver, no transmitter
[ 333.259034] em28xx 1-1.3.3:1.0: Input extension successfully initialized
[ 333.357610] tda18271: performing RF tracking filter calibration
[ 335.932682] tda18271: RF tracking filter calibration complete
[ 335.932775] em28xx 1-1.3.3:1.0: DVB: adapter 0 frontend 0 frequency 0 out of range (47000000..864000000)
pi@raspberrypi3:~ $

Starting Kodi/TV there are no errors shown in dmesg.

Raspberry Pi4 4GB
Raspbian Buster
Linux raspberrypi 4.19.97-v7l+ raspberrypi/firmware#1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l
Kodi Leia 18.6 Git:20200506-40c074c06b
Driver dvb-usb-terratec-h5-drxk.fw.

[ 1160.629549] usb 1-1.4: new high-speed USB device number 19 using xhci_hcd
[ 1160.761053] usb 1-1.4: New USB device found, idVendor=05e3, idProduct=0608, bcdDevice= 9.01
[ 1160.761069] usb 1-1.4: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ 1160.761083] usb 1-1.4: Product: USB2.0 Hub
[ 1160.765356] hub 1-1.4:1.0: USB hub found
[ 1160.766371] hub 1-1.4:1.0: 4 ports detected
[ 1161.079550] usb 1-1.4.3: new high-speed USB device number 20 using xhci_hcd
[ 1161.210660] usb 1-1.4.3: config 1 interface 0 altsetting 1 endpoint 0x82 has invalid wMaxPacketSize 0
[ 1161.211106] usb 1-1.4.3: New USB device found, idVendor=0ccd, idProduct=10b2, bcdDevice= 1.00
[ 1161.211112] usb 1-1.4.3: New USB device strings: Mfr=3, Product=1, SerialNumber=2
[ 1161.211118] usb 1-1.4.3: Product: TERRATCE H5 MKII
[ 1161.211123] usb 1-1.4.3: Manufacturer: TERRATEC
[ 1161.211128] usb 1-1.4.3: SerialNumber: 123456789ABCD
[ 1161.212631] em28xx 1-1.4.3:1.0: New device TERRATEC TERRATCE H5 MKII @ 480 Mbps (0ccd:10b2, interface 0, class 0)
[ 1161.212638] em28xx 1-1.4.3:1.0: Audio interface 0 found (Vendor Class)
[ 1161.212643] em28xx 1-1.4.3:1.0: Video interface 0 found: isoc
[ 1161.212648] em28xx 1-1.4.3:1.0: DVB interface 0 found: isoc
[ 1161.279604] em28xx 1-1.4.3:1.0: chip ID is em2884
[ 1161.355969] em28xx 1-1.4.3:1.0: EEPROM ID = 26 00 00 00, EEPROM hash = 0xbcd5a8cf
[ 1161.355975] em28xx 1-1.4.3:1.0: EEPROM info:
[ 1161.355980] em28xx 1-1.4.3:1.0: microcode start address = 0x0004, boot configuration = 0x00
[ 1161.362742] em28xx 1-1.4.3:1.0: I2S audio, 5 sample rates
[ 1161.362748] em28xx 1-1.4.3:1.0: 500mA max power
[ 1161.362754] em28xx 1-1.4.3:1.0: Table at offset 0x27, strings=0x2298, 0x1c6a, 0x1286
[ 1161.439550] em28xx 1-1.4.3:1.0: Identified as Terratec Cinergy H6 rev. 2 (card=101)
[ 1161.439557] em28xx 1-1.4.3:1.0: Currently, V4L2 is not supported on this model
[ 1161.439562] em28xx 1-1.4.3:1.0: dvb set to isoc mode.
[ 1161.439890] em28xx 1-1.4.3:1.0: Binding audio extension
[ 1161.439895] em28xx 1-1.4.3:1.0: em28xx-audio.c: Copyright (C) 2006 Markus Rechberger
[ 1161.439900] em28xx 1-1.4.3:1.0: em28xx-audio.c: Copyright (C) 2007-2016 Mauro Carvalho Chehab
[ 1161.439944] em28xx 1-1.4.3:1.0: Endpoint 0x83 high-speed on intf 0 alt 7 interval = 8, size 196
[ 1161.439950] em28xx 1-1.4.3:1.0: Number of URBs: 1, with 64 packets and 192 size
[ 1161.440140] em28xx 1-1.4.3:1.0: Audio extension successfully initialized
[ 1161.440146] em28xx 1-1.4.3:1.0: Binding DVB extension
[ 1162.026440] drxk: status = 0x439260d9
[ 1162.026454] drxk: detected a drx-3926k, spin A2, xtal 20.250 MHz
[ 1166.093774] drxk: DRXK driver version 0.9.4300
[ 1166.128472] drxk: frontend initialized.
[ 1166.128501] tda18271 8-0060: creating new instance
[ 1166.130489] tda18271: TDA18271HD/C2 detected @ 8-0060
[ 1166.581015] dvbdev: DVB: registering new adapter (1-1.4.3:1.0)
[ 1166.581037] em28xx 1-1.4.3:1.0: DVB: registering adapter 0 frontend 0 (DRXK DVB-C DVB-T)...
[ 1166.585327] em28xx 1-1.4.3:1.0: DVB extension successfully initialized
[ 1166.585345] em28xx 1-1.4.3:1.0: Registering input extension
[ 1166.585674] Registered IR keymap rc-nec-terratec-cinergy-xs
[ 1166.586085] rc rc0: 1-1.4.3:1.0 IR as /devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.4/1-1.4.3/1-1.4.3:1.0/rc/rc0
[ 1166.586306] input: 1-1.4.3:1.0 IR as /devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.4/1-1.4.3/1-1.4.3:1.0/rc/rc0/input17
[ 1166.586718] rc rc0: lirc_dev: driver em28xx registered at minor = 0, scancode receiver, no transmitter
[ 1166.586740] em28xx 1-1.4.3:1.0: Input extension successfully initialized
[ 1166.684004] tda18271: performing RF tracking filter calibration
[ 1169.340176] tda18271: RF tracking filter calibration complete
[ 1169.340259] em28xx 1-1.4.3:1.0: DVB: adapter 0 frontend 0 frequency 0 out of range (47000000..864000000)

Starting Kodi/TV:

pi@raspberrypi:~ $ dmesg
pi@raspberrypi:~ $ dmesg
[ 1634.827663] em28xx 1-1.4.3:1.0: write to i2c device at 0x52 failed with unknown error (status=1)
[ 1634.827669] drxk: i2c read error at addr 0x29
pi@raspberrypi:~ $ dmesg
[ 1634.827663] em28xx 1-1.4.3:1.0: write to i2c device at 0x52 failed with unknown error (status=1)
[ 1634.827669] drxk: i2c read error at addr 0x29
[ 1664.824224] drxk: ERROR: -32000
while sending cmd 0x0205 with params:
[ 1664.824232] drxk: 05 02 ..
[ 1664.824243] drxk: Error -22 on get_qam_lock_status
[ 1664.824251] drxk: Error -22 on get_lock_status
[ 1665.720279] drxk: i2c read error at addr 0x29
pi@raspberrypi:~ $ dmesg
[ 1634.827663] em28xx 1-1.4.3:1.0: write to i2c device at 0x52 failed with unknown error (status=1)
[ 1634.827669] drxk: i2c read error at addr 0x29
[ 1664.824224] drxk: ERROR: -32000
while sending cmd 0x0205 with params:
[ 1664.824232] drxk: 05 02 ..
[ 1664.824243] drxk: Error -22 on get_qam_lock_status
[ 1664.824251] drxk: Error -22 on get_lock_status
[ 1665.720279] drxk: i2c read error at addr 0x29
[ 1681.826525] em28xx 1-1.4.3:1.0: write to i2c device at 0x52 failed with unknown error (status=200)
[ 1681.826533] drxk: i2c read error at addr 0x29
[ 1683.826949] drxk: ERROR: -32768
while sending cmd 0x0205 with params:
[ 1683.826956] drxk: 05 02 ..
[ 1683.826967] drxk: Error -22 on get_qam_lock_status
[ 1683.826975] drxk: Error -22 on get_lock_status
[ 1688.827630] em28xx 1-1.4.3:1.0: write to i2c device at 0x52 failed with unknown error (status=200)
[ 1688.827641] drxk: i2c read error at addr 0x29
pi@raspberrypi:~ $

This Error-procedure goes on as long as the TV (Terratec H6) is playing and stops only when I stop TV