Re: TK1 System Freeze

[Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>]

Hi Marcel, Hi Thierry,

On 2017-11-20 00:57, Marcel Ziswiler wrote:
> Hi there
> 
> I lately was tasked to run some legacy Qt4e [1] application on Apalis
> TK1. It should really only draw directly to the Linux frame buffer
> /dev/fb0. Strangely as soon as that application is started the whole
> system freezes. Running it with the VNC backend or a pure frame buffer
> emulation it works just fine. So it must have something to do with the
> particular way the frame buffer is done on TK1. So far no attempt in
> debugging this any further bear any fruit. Whether stracing what the
> application is doing nor tracing the linux kernel side of things
> revealed where exactly the freeze happens. As I feared some kind of a
> configuration issue on Apalis TK1 I also tried the same on Jetson TK1
> with latest stock Linux kernel 4.14. However the same freeze happens.

This is still the case with 4.15-rc7.

While dd is not enough to reproduce it, using a simple fbdev application
such as ts_calibrate seems to be sufficient. Qt and ts_calibrate use
mmap for the framebuffer. The system seems to freeze when it tries to
write into the mapped area (at the memset line):
https://github.com/kergoth/tslib/blob/master/tests/fbutils-linux.c#L160

Is this a known problem? Any idea?

--
Stefan


> 
> Has anybody ever seen a similar complete system freeze? Any ideas what
> it may be or how we could debug this any further?
> 
> [1] https://layers.openembedded.org/layerindex/recipe/43622/
> 
> Cheers
> 
> Marcel