[Letux-kernel] Kernel v5.1-rc1 (was: LetuxOS Kernel v5.0-rc1)

H. Nikolaus Schaller hns at goldelico.com
Wed Mar 20 08:30:55 CET 2019


> Am 20.03.2019 um 08:19 schrieb Andreas Kemnade <andreas at kemnade.info>:
> Hi,
> On Tue, 19 Mar 2019 13:30:17 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>> Am 19.03.2019 um 13:16 schrieb H. Nikolaus Schaller <hns at goldelico.com>:

>>>>> * GTA04A4:	backlight ok, display shows white pixels only  
>>>> hmm, did a quick test with mainline: older dtb + 5.1-rc1 kernel = display ok
>>>> 5.1-rc1 kernel + dtb-5-1-rc1 (both mainline) = black screen  

Ah, I didn't read precisely: "black screen". I get this as well if I eliminate
most Letux patch sets.

This means that one or two hacks are not yet upstream...

> well,
> echo 0 >/sys/class/backlight/backlight/bl_power
> resolved that. Then I had a working display with mainline 5.1-rc1 + dtb-5.1-rc1
> I think we are talking about different problems.

Looks so...

My main symptom is that I get a /dev/fb0, X server process is running, backlight
is on, but the screen is completely white. And xset dpms force on/off can
turn backlight on&off. But still only white pixels.

I guess the problem is either the SPI interface to the panel or the pixel
clock/pixel data.

I am currently running a bisect to find out more.


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