Chrontel CH7036 chip not supported

[Carli]

I'm running a WeTab with ubuntu and the ch7036 chip is not supported.
There is a driver for the chromebook (called chrontel), but that driver is more or less a hacked daemon that sends some data to the chip and gives me the following error message:

Found device ID 0x56
Found revision ID 0x81
Mode 1366x786 (44)
1366y786, dot clock 69300000 -Hsync -Vsync
H: start 1414, end 1446, skew 0, total 1456
V: start 771, end 777, total 793
State: 0
Firmware size = 3295 bytes.
State: 2
State: 3
Timeout waiting for MCU to return EDID
CH7036 MCU ver 1.41, Device 56 rev 1 capability 0x1
EDID timed out: Ignore HPD because EDID failed just after firmware load
Get EDOD Failed (initial block) using 640x480@60
Could not find a useful resolution. Maybe hardware problem.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: xorg 1:7.7+1ubuntu4
ProcVersionSignature: Ubuntu 3.8.0-6.11-generic 3.8.0-rc7
Uname: Linux 3.8.0-6-generic i686
.tmp.unity.support.test.0:

ApportVersion: 2.8-0ubuntu4
Architecture: i386
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Wed Feb 13 10:46:06 2013
DistUpgraded: Fresh install
DistroCodename: raring
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller [8086:a011] (prog-if 00 [VGA controller])
   Subsystem: Device [1b0a:00c7]
   Subsystem: Device [1b0a:00c7]
InstallationDate: Installed on 2013-02-08 (4 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release i386 (20121017.2)
MachineType: PEGATRON WeTab
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-6-generic root=UUID=7cedb257-8646-45d8-a06b-c1a32d485cec ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/19/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: Lucid-GE-133
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: WeTab
dmi.board.vendor: PEGATRON
dmi.board.version: 30011578
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 1
dmi.chassis.vendor: PEGATRON
dmi.chassis.version: TT116A01
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrLucid-GE-133:bd11/19/2010:svnPEGATRON:pnWeTab:pvrTT116A01:rvnPEGATRON:rnWeTab:rvr30011578:cvnPEGATRON:ct1:cvrTT116A01:
dmi.product.name: WeTab
dmi.product.version: TT116A01
dmi.sys.vendor: PEGATRON
version.compiz: compiz 1:0.9.9~daily13.02.08-0ubuntu1
version.libdrm2: libdrm2 2.4.42-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.0.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.0.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.13.2-0ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.1.0-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.2-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.6-0ubuntu2
xserver.bootTime: Wed Feb 13 10:45:09 2013
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.13.2-0ubuntu2
xserver.video_driver: intel

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

We generally ask bug reporters to first request that the driver be added to the upstream kernel. This can be done by mailing the Linux Kernel Mailing List or opening a bug at bugzilla.kernel.org.

People affected by this bug are probably wondering why the kernel team doesn't just add the patch and fix it. The reason is that the kernel team is reluctant (not opposed) to apply any patch/driver to a kernel that is not from upstream. Applying patches and adding drivers that don't come from upstream add greatly to the support of the kernel as other upstream patches/drivers may touch the same area as the non-upstream patch and may prevent them from applying cleanly.

[Carli (s3734770)]

This driver is not a kernel driver, it is a daemon. It would be some effort to make a kernel driver out of it.

[Carli (s3734770)]

And even then, it is not assured that it will work. At least the chrontel driver did not work with my DVI-D screen. I don't actually know if it's a hardware problem (screen not supported), or a driver problem.
The error message says "hardware problem".

[Zhang Weiwu (zhangweiwu)]

A few days ago there was a post of a different workaround:

Installing the Chrontel Ch7036/HDMI - Output on Ubuntu
http://lackofalucidmind-en.blogspot.de/2014/01/hdmi-output.html

I tried following the instruction myself and to my surprise once the executable is launched (/usr/sbin/ch7036_start) it turns off my HDMI which was originally on (I had rebooted to Windows and had turned it on, and rebooted to Linux while it is still on). Perhaps that's because I am not using a chrome book. I used an x86-64 tablet, bModo 12, designed for Windows 7.

[Daniel Holz (daniel-holz91)]

I'm the creator of this blog. I'm using a WeTab which uses the same hardware as the bModo 12 so it should normally work. Did you try it when the hdmi was originally off?

[Zhang Weiwu (zhangweiwu)]

If I had HDMI turned off to start with, your method would not turn it on. There was no error message in the complete process following your instruction, but HDMI display shows 'no signal'.

$ sudo /usr/sbin/ch7036_start
/usr/sbin/ch7036_monitor: starts
Found device ID 0x56
Found revision ID 0x81
Mode 1024x768 (95)
1024x768, dot clock 65000000 -Hsync -Vsync
H: start 1048, end 1184, skew 0, total 1344
V: start 771, end 777, total 806
Firmware size = 3295 bytes.

As said, the device works on Windows 7.

I down-tuned the resolution, because even on Windows 7, the max resolution offered for HDMI is 1280x720, smaller than LVDS's native resolution and CH7036's advertised max resolution (both are 1366x768).

As you can see the resolution is 1024x768, that means in Linux I down-tuned it even lower than Windows 7, because in xrandr, the next resolution below 1366x768 is 1024x768.

 I was rather surprised when I look up the specs of WeTab and found that bModo has exactly the same configuration, including CPU type, memory, hard disk space and resolution. It really look like bModo 12 is just another casing of WeTab.

[Daniel Holz (daniel-holz91)]

Yeah there are many tablets like this. They are alll based on the Pegatron Lucid and sold under the name ExoPC, WeTab, Ciara Vibe, JS-Tab, W8Pad etc. Most come with Windows 7 but the WeTab came with its own Meego-based OS which had drivers for everything in the tablet.

Did you try some configuration options in /etc/chrontel-wetab.conf?

You could try the -E<number 1-6>-parameter for forcing some test edid numbers. Maybe with that the driver ignores the missing signal.
If that doesn't work you can force one of the following resolutions

0 - HDMI 640x480
 1 - HDMI 720x480
 2 - HDMI 1280x720
 3 - HDMI 1920x1080
 4 - HDMI 1920x1080
 5 - HDMI 720x576
 6 - HDMI 1280x720
 7 - HDMI 1920x1080
 8 - HDMI 1920x1080
 9 - DVI 640x480
10 - DVI 720x480
11 - DVI 720x576
12 - DVI 800x600
13 - DVI 1024x768
14 - DVI 1280x720
15 - DVI 1280x1024
16 - DVI 1440x900
17 - DVI 1680x1050
18 - DVI 1920x1080
19 - DVI 1600x1200
20 - DVI 1600x1200
21 - DVI 1600x1200
22 - DVI 1920x1200

with -M<modenumber>.

Even though the linux driver is a piece of crap it offers much higher resolutions. :D

[Carli (s3734770)]

@Maintainer: wouldn't it be better to integrate official support for that chip into ubuntu?

[Zhang Weiwu (zhangweiwu)]

Did any one try to make this work on Ubuntu 14.04?

On a different issue, does anyone know of a driver for Broadcom Crystal HD 1080p? VD920H it is, lspci lists:

02:00.0 Multimedia controller: Broadcom Corporation BCM70015 Video Decoder [Crystal HD]

How can I take advantage of that with VLC or mplayer? I know it is off-topic, but googling 10 minutes there is no right place to discuss this issue. Maybe you can throw me a link and I´ll discuss it elsewhere.

[Zhang Weiwu (zhangweiwu)]

The procedure on http://lackofalucidmind-en.blogspot.de/2014/01/hdmi-output.html if followed strictly except git-checking out latest code, not the specified revision, works on Ubuntu 14.04 64-bit too. Verified.

[Carli (s3734770)]

@Zhang Weiwu:
Thanks for that. It finally works for me.

@Maintainer:
Is there a chance that this tutorial instructions get packaged so that the driver can be installed easier?

[Zhang Weiwu (zhangweiwu)]

@carli

I guess it is easier and more useful to push for a change from Debian side, since multiple desk distros depend on Debian. Maybe close this one and re-file it in Debian? I don't know packaging to try it myself.

[Daniel Holz (daniel-holz91)]

I already thought about offering a package of the driver on my blog, but sadly even with some online tutorials I wasn't able to create a working package.