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

H. Nikolaus Schaller hns at goldelico.com
Thu Mar 21 08:05:45 CET 2019


Hi Andreas,

> Am 21.03.2019 um 07:18 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> On Thu, 21 Mar 2019 07:05:18 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> HI,
>> 
>>> Am 20.03.2019 um 16:31 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>> 
>>> Hi,
>>> 
>>>> Am 20.03.2019 um 08:30 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>>> 
>>>> Hi,
>>>> 
>>>>> 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 have now checked and the symptoms are two facets of the same problem.
>> 
>> When doing my git bisect of linus/master plus adding only 4 of our letux patches,
>> I get a black display in the error case which goes completely white when echoing to
>> bp_power.
>> 
>> I never had the backlight staying black but display working.
>> 
>> But there remains some difference by adding the full letux patch set. I.e. some
>> piece of code does have the same side effect as echo 0 >/sys/class/backlight/backlight/bl_power
>> 
> 
> Well, if I do that on mainline,

Hm. I am also doing that on mainline. Almost. Plus 4 patch sets which are not at all display related.

I have exactly these diffs to versions from linus/master:

iMac:master hns$ git diff --stat bisect
 Letux/README                        |   33 ++
 arch/arm/configs/letux_defconfig    | 6462 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 crypto/asymmetric_keys/Kconfig      |    1 +
 drivers/mtd/ubi/io.c                |    3 +-
 scripts/mod/file2alias.c            |    2 +
 scripts/sortextable.c               |    3 +
 security/selinux/include/classmap.h |    7 +
 7 files changed, 6510 insertions(+), 1 deletion(-)
iMac:master hns$ 

Besides letux_defconfig, most are to get the tree compiled (there are certain assumptions in upstream about the HOSTCC and
its #include files which a Darwin host does not exactly fulfill).

The ubi patch is to silence issues with not well formatted NAND.
The crypto diff is to select CONFIG_SYSTEM_TRUSTED_KEYRING (maybe this could
be done directly in letux_defconfig without patching the Kconfig).

So how exactly are you "doing that on mainline"? omap2plus_defconfig or letux_defconfig? Device tree from linus/master or the letux one?

What I have not yet tried is to boot on GTA04A5.

> I get a working display. Not only black screen.
> 
> So we probably have 
> a) some initilalisation race condition
> 
> or 
> 
> b) some memory corruption.
> 
> Both are nasty.

Indeed.

c) new compiler incompatibility

d) something incompatible in defconfig

BR,
Nikolaus



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