Colors of Noise

Following up on my port of the crystalhd plugin to the gstreamer 1.0 api I realized that the CrystalHD repo is pretty dormant. After reading slomo's nice article about GStreamer and hardware integration and a short off list mail exchange I decided to split the GStreamer part out of the CrystalHD repo and to try to get the plugin into gst-plugins-bad.

Since the kernel part is already in linux kernel's staging area there would not be much left in the repo except for the libcrystalhd library itself and the firmware blobs. So I split them out as well and started to clean them up a bit by moving it to autoconf/automake, dropping the need for a C++ compiler and adding symbol versioning among other things.

So up to know video is still smooth with:

gst-launch-1.0 filesrc location=sample.mp4 ! decodebin ! xvimagesink

after jhbuilding up to gst-plugins-bad.

There are #ifdefs for macosx and windows but I doubt they're functional but in case anybody is building libcrystalhd on these these platforms it'd be great to know if it still works.

Should these efforts lead to the crystalhd plugin being merged into GStreamer getting the kernel driver out of staging would be a great next step.

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Following up on using Debian on the WeTab with GNOME Shell I figured accelerated video using the built in CrystalHD to save battery power and CPU cycles would be nice to have. There's even a Debian package available but not for gstreamer 1.0 (which is used by GNOME 3.6) so I had a look at gstreamer's plugin writers guide and porting guide and updated the driver. Packages are here until there's a new upstream version or Debian package release.

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Following up on using Debian on the WeTab with GNOME Shell I had a look at automatically adjusting the screen orientation when rotating the device.

The accelerometer is handled in the asus_laptop module since kernel 3.2, so this shows up in /proc/bus/input/devices:

I: Bus=0019 Vendor=0000 Product=0000 Version=0000
N: Name="Pegatron Lucid Tablet Accelerometer"
P: Phys=pega_accel/input0
S: Sysfs=/devices/platform/asus_laptop/input/input4
U: Uniq=
H: Handlers=event4 js0 
B: PROP=0
B: EV=9
B: ABS=7

Whenever the screen orientation changes the driver emits a udev event. The helper in /lib/udev/accelerometer processes it thanks to /lib/udev/rules.d/61-accelerometer.rules, determines the orientation and adds the ID_INPUT_ACCELEROMETER_ORIENTATION property to the event which can be checked with udevadm monitor --property:

UDEV  [5778.534171] change   /devices/platform/asus_laptop/input/input4 (input)
ABS=7
ACTION=change
DEVPATH=/devices/platform/asus_laptop/input/input4
EV=9
ID_FOR_SEAT=input-platform-asus_laptop
ID_INPUT=1
ID_INPUT_ACCELEROMETER=1
ID_INPUT_ACCELEROMETER_ORIENTATION=right-up
ID_PATH=platform-asus_laptop
ID_PATH_TAG=platform-asus_laptop
MODALIAS=input:b0019v0000p0000e0000-e0,3,kra0,1,2,mlsfw
NAME="Pegatron Lucid Tablet Accelerometer"
PHYS="pega_accel/input0"
PRODUCT=19/0/0/0
PROP=0
SEQNUM=1550
SUBSYSTEM=input
TAGS=:seat:
UDEV_LOG=3
USEC_INITIALIZED=6154288

This is captured by gnome-settings-daemon (>=3.2) that adjusts the screen rotation using xrandr2 accordingly. This can be checked by running gnome-settings-daemon with --debug. The old way of using xinput events is no longer supported.

Unfortunately Debian's udev has a minor bug that misdetects the input device so this patch is needed to have the screen orientation changed automatically on the WeTab.

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