all buster builds (nightly) broken - usb and networking dont work

[sebastiannielsen]

Tried the buster builds, none of them work, usb and networking is broken. This on a rpi 2B. Guess its because it lacks bluetooth and wifi support and the build tried to activate that without support.

Since I can neither connect to ssh (due to broken networking) or connect a keyboard (due to broken usb) im unable to provide any form of logs or debugging info.

[guysoft]

Hey,

1. please providfe the exact file name of the zip you are using. There is a recent build 2019-08-24_2019-07-10-realtimepi-buster-lite-0.4.0.zip that might solve your issue. Without you providing I have no idea what you are testing.
2. The cmdline.txt has been changed in the nightly, please see:
   rpi-4.19-rt raspberrypi/linux#2943 (comment)
   The Rpi2 should work if you just update the cmdline.txt to how it looks in stable builds, example of that here.

[sebastiannielsen]

Following filenames were tested and did NOT work:

2019-06-29_2019-06-20-realtimepi-buster-lite-0.4.0.zip
2019-08-24_2019-07-10-realtimepi-buster-lite-0.4.0.zip

I checked and the cmdline is already changed per the linked comment in those builds.

[guysoft]

Ok - did you try changing the cmdline.txt BACK as given in the example?

[sebastiannielsen]

Now I tried with dwc_otg.lpm_enable=0 but the problem is that the boot process then stalls at finding /boot, then it can't find root filesystem, and then it starts emegency shell, afterwards it tries to sync NTP time but it can't since neither network or USB is working.

dwc_otg.lpm_enable=1 works booting from, but then usb and network don't work.

[guysoft]

@sebastiannielsen
Ok, this is a known bug, and you need to report it to: raspberrypi/linux#2943 (comment)

[sebastiannielsen]

Should I report it there when the latest official build (Raspbian Lite official 2019-07-10) does work flawlessly without any problems, and without any changes to cmdline?

Because the bug only comes when using your rt build.

[guysoft]

The thing is that the RT branch is in low priority and is maintained by @TiejunChina . The Rpi kernel developers are not really looking in to RT stuff. The usb-dwc_otg-fix which is suppose to make the system work both with USB and RT was writen by Oussama Ghorbel ghorbel@gmail.com which handle @oghorbel does not seem to be active.
I am not sure who has the technical knowhow to fix this. We might need a kernel developer to step in and save the day.

[sebastiannielsen]

How comes it that networking becomes borked by this fix?
I could live without USB if we could just get the networking to be happy.

or is the network card basically a USB network card "hardwired"`?

[guysoft]

The usb and ethernet share the same controller.

[TiejunChina]

Hi guys, I cannot understand why you don't open issue to https://github.com/raspberrypi/linux. Even I have no time to do something but rather than here, most developers are working on that official tree. If you're trying to maintain something else based on your CustomPiOS, you have to take the responsibilities to your repo. If you find something wrong with the official tree, please go there to open any issue. Even I don't take some necessary actions, more developers can see the issue and give you a feedback.

[sebastiannielsen]

@TiejunChina since the base repo (official raspberry repo) does not have any prebuilt RT binaries what I can see, I of course reported it here where the binaries where built.
The reason I want RT is that I intend running a NTP server and want as high accuracy as possible.

[guysoft]

@sebastiannielsen A realtime kernel is not relevant for an NTP server. You need a hardware element for a realtime clock. So as much as I value your debuging help, know its the wrong technology for your project.

[sebastiannielsen]

@guysoft and thats what I have, I have a GPS board with PPS output, and I also use the PPS kernel discipline. To improve the accuracy of this input processing of the PPS signal, I would want to use a RT kernel.

[guysoft]

Ah, my bad then. Didn't you are going all the way down to the signal processing of the PPS signal. There is code that does this freely available?

[sebastiannielsen]

yes, there is a kernel module that is shipped with the rpi image, that does all this signal processing and then exposes this as a /dev/pps0 device.