<erayt>
I want to implement decon for the Exynos 7870 close to mainline kernel. To be more specific, for my device
<erayt>
Because seems like simplefb just doesn't work.
<erayt>
My device is Samsung Galaxy J7 Pro and in the downstream dts (or the downstream exyno7870.dtsi) the compatible string was exynos5-decon or something like that
<erayt>
It's just isn't implemented in the mainline project.
<erayt>
The phone just hangs in the "Samsung Galaxy J7 Pro" logo, and when disabling always on for one or both of the regulators
<erayt>
(LDO_29 and 30)
<erayt>
it just goes to a black screen.
<erayt>
I can get ssh and USB Internet (from laptop to phone) just fine though.
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<erayt>
I'll provide logs as requested.
<erayt>
yeah I guess this place is dead.
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<erayt>
I guess I have no choice though.
<erayt>
Because I want to get the display working
<erayt>
krzk: Sorry for any interruptions, the pmOS mainlining wiki listed you as one of 3 persons to ask.
<krzk>
erayt: hey, but what is the question?
<erayt>
Well I'm trying to get the display working in the exynos 7870 mainline project for Samsung Galaxy J7 Pro
<krzk>
erayt: whatever downstream has in compatible means nothing because downstream does not care about DTS, bindings, compatibilpity etc.
<krzk>
erayt: this I understood from your messages, but what is the question
<erayt>
Well seems like simplefb isn't working. Is there a way to get decon set up?
<krzk>
erayt: I guess you need to implement the driver(s) for Exynos7870 DECON :)
<erayt>
Yes.
<erayt>
Also there's no nodes for it on the dtsi
<erayt>
I have the s6e3fa3 panel, which the driver for it is not present in the mainline source
<erayt>
At least the one that I'm using.
<erayt>
The msm 8996 close to mainline linux kernel has it because one of the Oneplus 3T models use the s6e3fa3 panel.
<erayt>
So, how can I implement it? Any guides to help me out?
<erayt>
also there's no detailed schematics and no detailed info for J7 Pro anywhere on the net.
<krzk>
erayt: implementing from scratch would be a lot of work, so guide is to extegnd existing support. Now, it depends how different it is from Exynos7 (as in 7420) or Exynos5433.
<krzk>
erayt: downstream code can help you - usually you compare downstream 5433 with downstream 7870 or 7420 with 7870 and based on this decide to which driver you add 7870
<krzk>
and of course what you need to add
<erayt>
Well 7420 is used on phones?
<krzk>
and then you keep adding missing features, ops, hooks, quirks for new DECON driver
<krzk>
All Exynos are usedon phones, so yes, 7420 as well
<erayt>
because 5433 had tv output I think
<krzk>
there are just few exceptions where they aren't
<erayt>
this was the string I'm talking about btw
<erayt>
samsung,exynos5-decon_driver
<erayt>
I'll compare 5433 first
<erayt>
Which dtsi would be fit more?
<erayt>
exynos 5433 decon is in a different address
<krzk>
erayt: address matters less, although could be hint. Most likely 7870 hardware is closer to 7420 than to 5433. But DECON in 5433 was really nicely developed and tested. Decon in 7420 - no clue. Maybe it wasn't ever working.
<erayt>
which one is 7420?
<krzk>
erayt: anyway your questions are now not specific to decon, so standard guide for mainlining vendor drivers apply - like comparing vendor drivers to figure out some things.
<erayt>
okay.
<krzk>
What do you mean? Exynos7420 is Exynos7420.
<krzk>
It's probably close to what we have in-tree: Exynos7
<erayt>
Well seems like it doesn't have decon there either
<krzk>
I just checked and there is...
<krzk>
just in case we talk about the same thing - here is the driver: drivers/gpu/drm/exynos/exynos7_drm_decon.c
<erayt>
ah okay.
<erayt>
Alright found it.
<erayt>
I guess I'll look at the file itself and the includes.
<erayt>
and try to find the nodes and clock names etc.
<krzk>
anyway DECON is just one piece. You need proper clock tree and there is nothing in mainline kernel :/. Plus you need other parts of display pipeline, like MIPI DSI or other outputs.
<erayt>
Well yeah I know.
<krzk>
Another point is that people instead of mainlining some phone Exyos SoCs, they create one more fork. I don't have any interest in such forks, it is not mainline. It is not upstream.
<krzk>
So till there is no base support (e.g. serial console, storage, whatever basic), I don't think it is worth even thinking about display, which is one of the trickiest/biggest part to do.
<krzk>
Anyone of course can create as many forks as one wishes. I just don't care about these forks :(