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 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
