[Letux-kernel] LetuxOS Kernel: Status

H. Nikolaus Schaller hns at goldelico.com
Sat Jun 20 23:05:19 CEST 2020

after upgrading to v5.8-rc1 and fixing some older issues, I have spent the week with
testing of multiple kernel variants on most boards we support (more testers would
be helpful of course).

The current status can be summarised as:
* GTA04 is working well (with no new issues beyond the known ones)
* OpenPandora working well (with no new issues beyond the known ones)
* PandaBoard ES has problems with Ethernet, USB-gadget and partprobe for letux-5.6.y and later
  twl6040 audio is only working with letux-4.19.y (but speaker gets hot indicating a big DC offset)
* Pyra is working with letux-5.4.y and 5.6.y incl. patches by Dave Shah for TILER screen rotation,
  Etnaviv setup and PVRSGX improvements.
  4.19.y isn't booting reliably (at least LPAE build) - sometimes hangs after Starting Kernel...
  5.7.y and 5.8-rc1 boot on 4GB RAM only (stumbles on 2GB with "missing hwmod/omap_dev info")
  but there is no /dev/fb0 and backlight remains black (although brightness is set)
  This has been tested on an older 2GB RAM Pyra (HW v5.1) and a mass (pre)production Pyra with 4GB RAM (HW v5.3)
* BeagleBone with LCD cape is working, except 4.19.y which has no LCD and backlight
* PinePhone, CI20, Udoo neo, RasPi and Tolino are not yet tested but I don't expect bigger problems
  and if there are, they can be fixed in future v5.8 release candidates

Please note that v5.6 is now [EOL] i.e. there will be no upstream patches any more.
And note that letux-5.7 has switched the default PVRSGX release to DDK 1.17 which
is more modern (but 1.14 and some others are still included) and runs the same on
omap3, omap4 and omap5.

As a general observation of problems, twl6040 audio doesn't work after 4.19
(on PandaBoard and Pyra). It is good that we have two quite different systems to test
(OMAP5 uEVM has no connection for handsfree speakers and there may be differences
between omap4 and 5).

I want to take a look at this since I have a quite clear picture what got more and
more broken (internal APIs have changed and initialization isn't correct any more),
but please do not expect quick miracles since I have to fix the Pandaboard issues
first so that a modern kernel (at least v5.4) works there without other troubles.

And I have to do that in my spare time (like most of us) which makes such topics get a
quite low priority, because they are a lot of Sisyphos work (and not fun or anything
to learn something important).

As a first step, I have now started the build server and the kernel builds will
be updated in the next hours (and reported here by automatically generated mail).
Hopefully before v5.8-rc2 and new stable releases appear upstream.

BR and thanks,

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