[Letux-kernel] Debugging 4.11-rc6 on GTA04

Tue Apr 11 20:28:11 CEST 2017

> Am 11.04.2017 um 20:22 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> On Tue, 11 Apr 2017 20:10:52 +0200
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> 
>>> Am 11.04.2017 um 19:49 schrieb Andreas Kemnade <andreas at kemnade.info>:
>>> 
>>> On Tue, 11 Apr 2017 15:36:32 +0200
>>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>> 
>>>> Hi Andreas,
>>>> 
>>>>> Am 11.04.2017 um 12:43 schrieb Andreas Kemnade <andreas at kemnade.info>:
>>>>> 
>>>>> On Mon, 10 Apr 2017 22:01:28 +0200
>>>>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>>>> 
>>>>>> 
>>>>>>> Am 10.04.2017 um 20:13 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>>>>>> 
>>>>>>> Hi,
>>>>>>> I have found a little time to upgrade our tree to 4.11-rc6
>>>>>>> and for the first time there were no kernel oops on the GTA04(A5)
>>>>>>> until login.
>>>>>>> 
>>>>>>> Only the LCD is broken :(
>>>>>>> 
>>>>>>> On the Pyra the same kernel works well. So it seems to be
>>>>>>> OMAP3 specific (maybe again some interference of the TILER
>>>>>>> addition, but I can easily check by merging my 4.11-rc6
>>>>>>> without TILER).
>>>>>> 
>>>>>> I have now built w/o TILER and for the first two boot attempts I had the
>>>>>> same error. But the third one succeeded. This time I got
>>>>> [...]
>>>>>> 
>>>>>> And the ethernet gadget was not loaded (initially). No VBUS event reported. But charger started charging.
>>>>>> 
>>>>>> After unplugging the USB cable I got:
>>>>>> 
>>>>>> root at letux:~# [  230.016326] musb-hdrc musb-hdrc.0.auto: VBUS_ERROR in b_idle (90, <VBusValid), retry #0, port1 00000100
>>>>>> 
>>>>>> And then:
>>>>>> 
>>>>>> [  237.857330] g_ether gadget: high-speed config #1: CDC Ethernet (ECM)
>>>>>> [  238.624481] IPv6: ADDRCONF(NETDEV_CHANGE): usb0: link becomes ready
>>>>>> 
>>>>>> Otherwise I didn't see any significant issue.
>>>>>> 
>>>>>> So it looks as if we still have two bugs: one in musb and another one in TILER/crtc.
>>>>>> 
>>>>> Sounds like problems which can be bisected on mainline. I think I will
>>>>> bisect this evening a bit. With musb, there is probably just another
>>>>> enable/disable balancing problem which must be somehow worked around in
>>>>> the glue layer or phy.
>>>> 
>>>> Good ideas!
>>>> 
>>>> But this gave me another idea... I have added a command line option to my
>>>> merge script so that it ignores the mergefile. Then I can add a handful
>>>> of our feature branches to be merged on top of letux-base.
>>>> 
>>>> With these ones, I could get it compiled and run on the GTA04A5 (of course missing sound,
>>>> inverted touch etc.):
>>>> 
>>>> ./merge -p -nmf -- work/hns/letux/rootfs work/hns/dt/gta04 work/hns/dt/gta04a5 work/hns/mtd/onenand work/marek/generic-adc-battery work/hns/misc/w2sg-serdev
>>>> 
>>>> Result is at:
>>>> 
>>>> http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/letux-4.11-rc6%2Brootfs%2Bgta04%2Bgta04a5%2Bonenand%2Bgeneric-adc-battery%2Bw2sg-serdev
>>>> 
>>>> Interestingly our feature branches are not as independent as they should
>>>> be... The generic adc battery is needed for some #include in the GTA04DT and
>>>> GTA04A5 wants to modify a bluetooth node that comes through the w2sg-serdev
>>>> branch.
>>>> 
>>>> Anyways, the important information is: with this minimum set of feature branches
>>>> I have neither problems with musb nor display. So the issue is not coming from
>>>> mainline...
>>>> 
>>> Well, I have just a white screen here with that. So, there is more...
>> 
>> Hm. That is unexpected... I am not 100% sure if I did a clean build.
>> 
>>> 
>>> AFAICR, the most important this
>>> missing in twl4030_charger are the things to have detection working when
>>> the stuff is loaded. So for mainline experiments, the idea would be to
>>> build musb/twl stuff not as modules. And keep our device tree.
>> 
>> Well, the strangest thing is that I have merged all the listed branches on
>> top of letux-base and all of them work.
>> 
>> So I am either making a systematic mistake or the real bug is outside of the
>> musb/twl4030 subsystem.
>> 
> I checked 4.10.0 mainline + letux-4.11-rc6 feature branch -> working
> display (besides of non-calibrated touchscreen, could log in via usb
> 
> mainline 4.11-rc6 funny moving stripes on the display, no usb.

Ah, you mean mainline. I haven't tested that but letux-base which has some
old (but probably important) patches we have not yet extracted into separate
feature branches. Recently I worked out a strategy but it is still a lot
of manual work (resolve rebase conflicts).

> 
>> I think I will have to bisect the mergefile until I find the problematic
>> feature branch...
> 
> I still blame mainline. But I do not like these bugs which happen only
> sometimes.

letux-base plus some minimal feature branches for the GTA04A5 work,
but the full set doesn't. So it is something in the set of our feature branches.

I have now set up a simple mechanism to bisect this (a text file with the
list of branches to merge and an indicator where to stop processing).

BR,
Nikolaus

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