[Letux-kernel] Long-Term kernels

H. Nikolaus Schaller hns at goldelico.com
Fri Jan 29 09:51:27 CET 2021

Hi Tomi,

> Am 29.01.2021 um 09:02 schrieb Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>:
> Hi,
> On 21/12/2020 21:12, H. Nikolaus Schaller wrote:
>>> Am 21.12.2020 um 19:59 schrieb David Shah <dave at ds0.me>:
>>> I am just repeating
>>> xset dpms force off
>>> xset dpms force on
>>> until it fails - once it's failed you can get it to come back by
>>> running the sequence of commands again a few times.
>> Ah, ok. Haven't tried that ever on the Pyra :)
>> Maybe because I had trouble waking up my HDMI-Monitor when running Letux
>> kernel on the RasPi 3B+. So I thought that the command is somehow broken.
>>> Note that this is with the OMAP5 X11 driver - 
>>> https://dev.pyra-handheld.com/packages/xserver-xorg-video-armsoc-omap5
>>> I can't see a particularly concerning difference between our disable
>>> function (which is where the problems seem to start) and other panel
>>> drivers. I half wonder if the problem might be in the OMAP DSI stuff
>>> rather than the panel driver.
>> Yes, it is unlikely a problem of the panel driver (which follows structure
>> of the otm8009a driver which is used by some STM mipi dsi host). As said
>> Tomi was not sure about the OMAPDRM driver doing all sequencing
>> correctly.
>> So let's wait until the new OMAPDRM subsystem arrives in linux-next and
>> then submit fixes we can also backport to our letux-5.10.y series.
> I haven't had time to look at any OMAP stuff lately. Are things still
> broken?

It seems to work fine :) And we have integrated it into our letux-5.11-rc tree.

I am just waiting for the new DSI drivers arrive in v5.12-rc1 and then 
we can start to upstream our panel driver...

And watch out for bugs and issues. For example if the sequencing works right
in all situations (driver built into kernel or module loading rescheduled by
deferred probing).

What I meant above is is that the long term kernel v5.10 is not compatible
to the new panel driver and I think we should backport the new omap DSI driver
and panel driver.

> Also, unfortunately my old OMAP5 uevm + a nonsupported DSI videomode
> panel is not working anymore at all (it was slightly broken already
> before but sometimes worked), so I don't have any DSI videomode device.

Maybe Michael can arrange something regarding the missing Pyra case for
the Pyra boards he did send to you (if you didn't send them back). A
completely assembled Pyra is much easier to handle for boot and development
than a disassembled one in a lab setup.


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