[Letux-kernel] Strange things happening with latest kernels

H. Nikolaus Schaller hns at goldelico.com
Thu Jun 13 19:16:56 CEST 2019


> Am 13.06.2019 um 18:46 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> 
>> Am 13.06.2019 um 18:33 schrieb Andreas Kemnade <andreas at kemnade.info>:
>> 
>> Hi,
>> 
>> On Thu, 13 Jun 2019 18:08:12 +0200
>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>> 
>>>> Am 13.06.2019 um 17:51 schrieb Andreas Kemnade <andreas at kemnade.info>:
>>>> 
>>>> On Thu, 13 Jun 2019 15:45:42 +0200
>>>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>>> 
>>>>>> Am 13.06.2019 um 11:08 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>>>>> 
>>>>>> 
>>>>>> Something which needs deeper inspection to understand the influencing
>>>>>> factors.    
>>>>> 
>>>>> As soon as I start X11, temperature goes up. Battery temp to 55.1°C and OMAP3
>>>>> reports 90°C during charging.
>>>>> 
>>>> Strange thing, Does it depend on how X is accessing the fb (omapfb vs. fbdev vs. modesetting
>>>> driver)? SGX active vs. not active.  
>>> 
>>> Have not yet tested into that direction. SGX is not compiled into any of the
>>> kernels I have tried.
>>> 
>>> Next thing is to test with LXDE or XfCE. And try a build with omap2plus_defconfig.
>>> 
>> maybe there are multiple problems working together to heat up omap3.
> 
> Yes, looks so. I just never had experienced that on OMAP3 before. Just
> on OMAP5...
> 
>> I doubt cpufreq alone causes such problems. But I will test, if
>> everything is idle, things should be powered down anyways regardless of
>> cpufreq
>> 
>> When I had a hot gta04 in the past, it was always at a bad time.
>> Touchscreen did not work. Last time was when I wanted to use the gta04
>> to show me the way from Brussels midi to my hotel for fosdem. That
>> was with 4.17 kernel.
> 
> And strangely there aren't many recent omap3 specific changes in 4.19..4.19.49
> 
> iMac:master hns$ git log v4.19..v4.19.49 --oneline arch/arm/mach-omap2/
> 30d503bae967 ARM: avoid Cortex-A9 livelock on tight dmb loops
> f49f7007de59 ARM: OMAP2+: fix lack of timer interrupts on CPU1 after hotplug
> f3f7a8b6faf8 ARM: OMAP2+: Variable "reg" in function omap4_dsi_mux_pads() could be uninitialized
> 1b1de8b95b97 ARM: OMAP5+: Fix inverted nirq pin interrupts with irq_set_type
> 8218fcf4666c ARM: OMAP2+: hwmod: Fix some section annotations
> 5a8fbba77bf8 ARM: OMAP2+: prm44xx: Fix section annotation on omap44xx_prm_enable_io_wakeup
> iMac:master hns$ 
> 
> So it might be some (clock?) driver but there are just 2 patches in drivers/clk/ti.
> 
> Maybe I just never had recognised this because the room temperature was lower?

Or it did degrade with every kernel upgrade since 4.19-rc1 and I rarely can do stress
tests with every new kernel version, just check basic functions (display, touch, USB,
charger, sound) or things explicitly backported/improved.

> On the other hand, the GTA04 is really getting hot (with risk for battery damage).

Ok, with LXDE it is initially (after boot) at ca. 70% 800MHz
but degrading to 20%@800MHz 5 minutes after boot and 

It has a little less system load in "idle" than QuantumSTEP, but 10% vs. 2%
should not make such a big difference.

top - 00:03:25 up 3 min,  2 users,  load average: 0.44, 0.60, 0.27
Tasks:  85 total,   1 running,  56 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.7 us,  1.3 sy,  0.0 ni, 97.1 id,  0.0 wa,  0.0 hi,  1.0 si,  0.0 st
KiB Mem:    507084 total,   160996 used,   346088 free,    10476 buffers
KiB Swap:        0 total,        0 used,        0 free.    93440 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                                                                                                                                                                                                 
 3612 root      20   0    3100   1804   1384 R  1.6  0.4   0:00.89 top                                                                                                                                                                                                                     
 3606 root      20   0    9988   3992   3392 S  0.7  0.8   0:00.36 sshd                                                                                                                                                                                                                     
   17 root      20   0       0      0      0 I  0.3  0.0   0:00.14 kworker/u2:1-ev                                                                                                                                                                                                         
   19 root      20   0       0      0      0 I  0.3  0.0   0:00.54 kworker/0:1-eve                                                                                                                                                                                                         
 3054 root      20   0   52060  15444  12588 S  0.3  3.0   0:07.88 lxpanel                                                                                                                                                                                                                 
    1 root      20   0    2372   1224   1088 S  0.0  0.2   0:03.10 init                                                                                                                                                                                                                     
    2 root      20   0       0      0      0 S  0.0  0.0   0:00.00 kthreadd                                                                                                                                                                                                                 
    3 root       0 -20       0      0      0 I  0.0  0.0   0:00.00 rcu_gp                                                                                                                                                                                                                   
    4 root       0 -20       0      0      0 I  0.0  0.0   0:00.00 rcu_par_gp                                                                                                                                                                                                               

Temperature is also growing:

root at letux:~# ./temperatures 
Sat Jan 1 00:06:58 UTC 2000 67° 33° 4158mV 800MHz
root at letux:~# 

But: I did run the "high-load" script which tries to do a 100% load on each
ARM core (developed for heating up the Pyra) and there, the SoC temperature
slowly creeps up to 84°C and battery is at 41°.

And after stopping this process it goes down to the 75° and 45° which I
remember to be some thermal equilibrium with radiation to the surrounding
air.

So something in the OMAP3 SoC can be getting hotter than it IMHO should...

Maybe I should also compare to the 4.14 kernels. And try to look with the
thermo-image camera if it is really the OMAP3 and not e.g. the WLAN chip
which is close.

Much more work than planned for...

BR,
Nikolaus



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