TechnoTrend TT-TVStick CT2-4400 (v2) stopped working with kernel 4.18

[Mitsch]

Dear developer(s),

I used a vdr-installation on Debian testing, before. Switched over to Ubuntu since the release of cosmic because of problems with GPU/steam under Debian. Now, I have problems to configure vdr because my TV stick doesn't seem to work with kernel 4.18.
This is what I did: Installed Ubuntu, upgraded via aptitude to the latest packages, got the firmware "dvb-demod-si2168-b40-01.fw" and "dvb-tuner-si2158-a20-01.fw" (as it was recommended by *I guess it was* openelec.org and the modinfo output of si2168 and si2157), tried w_scan and failed (w_scan *can* find some signals but failes in getting the channels). That looks like this, f.e.:

[…}
Scanning DVB-T2...
474000: (time: 01:38.796)
482000: (time: 01:43.155)
490000: (time: 01:45.163) signal ok: QAM_AUTO f = 490000 kHz I999B8C999D999T999G999Y999P0 (0:0:0)
        Info: no data from PAT after 2 seconds
        deleting (QAM_AUTO f = 490000 kHz I999B8C999D999T999G999Y999P0 (0:0:0))
[…]

Now, I tried an older kernel - 4.15, because it's still in the cosmics' repository and tried w_scan again: Success, although the TV-Stick doesn't find all the channels I found with Debian Testing.

So, maybe there's a regression in the latest kernel regarding the TV-Stick-driver or there is another firmware which will work better with 4.18…?

Would be glad if someone could help to work that out…

Greets!

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: linux-image-4.18.0-10-generic 4.18.0-10.11
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: jarosch 1516 F.... pulseaudio
 /dev/snd/controlC0: jarosch 1516 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 26 23:32:50 2018
InstallationDate: Installed on 2018-10-24 (2 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
IwConfig:
 lo no wireless extensions.

 enp3s0 no wireless extensions.
MachineType: BIOSTAR Group Hi-Fi A88S3+
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.18.0-10-generic root=UUID=e5ad9e21-ba9d-4f5e-9100-374ea87d4eba ro rootflags=subvol=@ pti=off spectre_v2=off l1tf=off nospec_store_bypass_disable no_stf_barrier quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.18.0-10-generic N/A
 linux-backports-modules-4.18.0-10-generic N/A
 linux-firmware 1.175
RfKill:
 0: hci0: Bluetooth
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/18/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.5
dmi.board.asset.tag: None
dmi.board.name: Hi-Fi A88S3+
dmi.board.vendor: BIOSTAR Group
dmi.chassis.asset.tag: None
dmi.chassis.type: 3
dmi.chassis.vendor: BIOSTAR Group
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd03/18/2015:svnBIOSTARGroup:pnHi-FiA88S3+:pvr:rvnBIOSTARGroup:rnHi-FiA88S3+:rvr:cvnBIOSTARGroup:ct3:cvr:
dmi.product.family: None
dmi.product.name: Hi-Fi A88S3+
dmi.product.sku: None
dmi.sys.vendor: BIOSTAR Group

[Cristian Aravena Romero (caravena)]

Would it be possible for you to test the latest upstream kernel? Refer
to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
v4.19 kernel[0].

If this bug is fixed in the mainline kernel, please add the following
tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag:
'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as
"Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.19

[Mitsch (kontakt-riotmusic)]

Yes, tried an unsigned kernel of [0] (linux-image-unsigned-4.19.0-041900-generic_4.19.0-041900.201810221809_amd64.deb with linux-modules-4.19.0-041900-generic_4.19.0-041900.201810221809_amd64.deb) and it shows exactly the same behaviour as cosmic's default kernel.

Forgot to mention: w_scan closes with error message
"ERROR: Sorry - i couldn't get any working frequency/transponder
 Nothing to scan!!"

Unfortunately the Debian installation where everything went fine was on the same SSD I installed Ubuntu, now. So, I can't verify if the firmware I used there was exactly the same. On the other hand, 4.15 (kind of) works with ubuntu cosmic, so, IMHO and speaking as a layman this looks like a regression to me…

[Rick (rick.ashley)]

I think this is caused by commit

1a0c10ed7bb191bccf6f1e2d16203886a5ce76c8
media: dvb-usb-v2: stop using coherent memory for URBs

Reverting this should restore normal operation.

[Mitsch (kontakt-riotmusic)]

Can I do anything about it or does it depend on Ubuntu- or even kernel-maintainers to deliver a kernel that is working with the stick, again? Do you think it will land in a future version of the 4.18 kernel (of Ubuntu) (, soon)? Just to evaluate if it's worth it looking for alternatives…

[Rick (rick.ashley)]

4.18 EOL now anyway

The only way out is to revert the above commit this patch isn't yet upstream
https://patchwork.linuxtv.org/patch/53155/

Also this patch which has made into kernel 4.18
commit 7d95fb746c4eece67308f1642a666ea1ebdbd2cc
Revert "media: dvbsky: use just one mutex for serializing device R/W ops"

[Mitsch (kontakt-riotmusic)]

Sorry for being such a noob, but does that mean, if I use a 4.20-kernel from somewhere (self-baken or found in a repository of a future ubuntu-version) I could be lucky and everything works as with kernel 4.16?

[Rick (rick.ashley)]

Kernel 4.21.1 and 4.19.14 have all the fixes.

[Rick (rick.ashley)]

Sorry I meant 4.20.1

[Rick (rick.ashley)]

In addition to above commit
255095fa7f62ff09b6f61393414535c59c6b4cb0
media: dvb-usb-v2: Fix incorrect use of transfer_flags URB_FREE_BUFFER

[Mitsch (kontakt-riotmusic)]

Thanks! Can't wait to test the kernels, once they're out for ubuntu…

[Kai-Heng Feng (kaihengfeng)]

The patch in #7 is already in latest Cosmic kernel. Does it solve the issue? If not, I'll build a test kernel with commit in #11.

[Mitsch (kontakt-riotmusic)]

Thanks for the service! Yes! It works, again, as before! Guess, you can close the bug…