[Letux-kernel] Pyra display driver once again broken in v5.2-rc1

H. Nikolaus Schaller hns at goldelico.com
Mon May 27 14:46:04 CEST 2019

unfortunately every year or so some upstream change breaks
our (still out-of tree) DSI panel driver for the Pyra(Phone).
This time it happened with v5.2-rc1.

v5.2-rc1 also broke the GTA04 display and the L3704/L7004 displays,
but those are DPI panels and the reasons were two separate
issues which have nothing to do with the Pyra DSI panel.

There have been some API changes for DSI panel drivers and
I have done a

	git diff v5.2-rc1 v5.1 drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c

to identify them and tried to apply similar patches to our
panel. But still the driver is successfully probed, but shows
not activity. No calls to enable() or connect(). Backlight stays
black. And as a result there is also no /dev/fb0, text console
or X11.

Unfortunately, it has not improved after upgrading to v5.2-rc2.

So once again it appears that I have to git bisect upstream
patches to find out what is going on...

Maybe I should look for more attractive and innovative projects
than hunting such bugs in my spare time. Or look for someone who
takes care of maintaining the panel driver...

Anyways, ideas what could be wrong or missing are welcome.

I have pushed all code to the pyra-minimal tree so that it
is just a handful of commits on top of v5.2-rc2 (can be compiled
with omap2plus_defconfig as well).



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