Letux Kernel


You are looking at an old revision of the page UpstreamStatus. This revision was created by Andreas Kemnade.

Table of Content

Upstream status for GTA04

Upstream status GTA04 4.20

Generally a lot of things are useable, so in many cases patches can be develop on top of mainline


  • Modem-Port:

    • working, but suboptimal pm
    • phy reset workaround missing, giving additional 10mA suspend current if ehci-omap is loaded requires off-mode-enabled (which is enabled in mainline only via a debugfs file)
    • wwan-on-off missing (on gta04a4/5 gpio186 needs to be manually triggered via userspace to enable/disable modem
  • OTG-Port

    • working but some feature missing:
      • id pin status sysfs file missing
      • b_host hacks missing
      • The minimum level the vbus voltage is allowed to drop to while increasing charging current is higher on mainline


  • mostly working
  • libertas (GTA04A4)
    • Mainline has low transfer rate (100KByte/s)
      • Reason: sdio irq not enabled, that should be a simple one-liner patch to dtb. But somehow it is not working easily. Letux kernels have our own workaround giving higher transfer rates.
    • higher power consumption when device is up but not connected (connect to save power), probably not wise to uptream that without cleanly solving the irq problem
  • wl18xx (GTA04A5): working in mainline as well as in letux


  • problematic
  • GTA04A4
    • reset handling bt vs wlan is missing, so problems arise if one tries to use bluetooth without wlan
    • h4 serdev additions are missing (is in discussion with upstream, probably hci_uart will be replaced by a new bt_uart), so pm is not working
  • GTA04A5
    • device tree for hcill is missing (things should be ready for uptream)


  • missing, vsim needs to be switched on and gpio145 needs to be toggled
  • patchset is in review, no conceptual issues

Fuel Gauge access

  • if soc is in too deep powersave, reading out the hdq status fails, there are patches to the clock framework in letux-kernel to fix this

Off mode

  • off mode needs to be manually enabled via debugfs, that is a lower power mode in the soc which reduces suspend current by around 5mA and helps with some ehci problems.


  • only main audio and the socmodem link are working
  • no hw routing between modemtwl4030
  • fm and bluetooth audio devices are missing


  • calibration is missing, workaround:

    uname -r | grep -E 'letux' || xinput set-prop "TSC2007 Touchscreen"  "Evdev Axis Calibration" 256 3840 3840 256
  • conceptual issues with upstreaming that


  • missing, no support for applications using accelerometer via evdev, they are required to use iio

Created: 5 years 6 months ago
by Andreas Kemnade

Updated: 5 years 6 months ago
by Andreas Kemnade

Old Revisions