Hi,
Am 20.03.2019 um 08:30 schrieb H. Nikolaus Schaller hns@goldelico.com:
Hi,
Am 20.03.2019 um 08:19 schrieb Andreas Kemnade andreas@kemnade.info:
Hi,
On Tue, 19 Mar 2019 13:30:17 +0100 "H. Nikolaus Schaller" hns@goldelico.com wrote:
Am 19.03.2019 um 13:16 schrieb H. Nikolaus Schaller hns@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.
First result:
67e79a6dc2664a3ef85113440e60f7aaca3c7815 is the first bad commit
i.e.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
But what does this have to do with the GTA04 display and backlight power???
I fear a side-effect of an array out of bounds write like we did have a while ago.
Or I did make a mistake in reporting good/bad to git bisect. Maybe I should repeat.
Note this is using mainline linux (bisected) + letux/compile-fixes + letux/arm_defconfig + letux/Letux + letux/ubi-fs and nothing else. So it does not include many of the Letux hacks.
BR, Nikolaus