<mikhail.avkhimenia <at> emlid.com> writes: > > Hello, > > Recently, Raspberry Pi Foundation presented and started selling new Raspberry Pi 2 SBC. It’s based on > BCM2709 processor, which is an upgraded version of BCM2708. The main difference is that old BCM2708 has > one core and its architecture is ARMv6, while the new BCM2709 has 4 cores and ARMv7 architecture. Most of > the peripheral blocks are the same - DMA, I2C, UART, etc. > > RT patch has been working very well (after fixing the sd driver a couple of years ago) with Raspberry Pi 1 and > kernel 3.12. > With the release of the new board Raspberry Pi Foundation also switched to the new kernel version - 3.18, > support for Raspberry Pi 2 has been introduced in that version. > I applied patch-3.18.7-rt2 on RPi’s kernel fork and built two kernels - one for Raspberry Pi 1 and another > one for Raspberry Pi 2. > On older Raspberry Pi 1 3.18.7-rt2 seems to work without any problems, I ran cyclictest and stress and it > performed well. > But on new Raspberry Pi 2 I’m experiencing frequent freezes. > > Steps to reproduce: > 1. Clone https://github.com/raspberrypi/linux , checkout 3.18.7 - 0be82f722c097340632a59b879fbfee9c6148f53 > 2. Apply patch-3.18.7-rt2 > 3. (optionally) apply “[RT PATCH] mmc: sdhci: don't provide hard irq handler” > 4. Make menuconfig bcm2709_defconfig > 5 Configure: full rt preemption, periodic ticks, performance governor as default and optionally > preemption debugging > 6. Compile kernel & modules > 7. Copy Image to /boot/kernel7.img and arch/arm/boot/dts/bcm2709-rpi- 2-b.dtb to > /boot/bcm2709-rpi-2-b.dtb, copy modules. > Boot and run: sudo cyclictest --smp -p51 -m > > The bad thing is that it freezes without any message, even with preemption debug information and lockup > detection enabled. > > Here’s how it happens: > 1. I connect to Raspberry Pi 2 over serial > 2. I connect to Raspberry Pi 2 over Ethernet or WiFi > 3. In the ssh terminal I run “sudo cyclictest --smp -p51 -m”, it works for 30 seconds and the terminal > hangs. LEDs on WiFi or Ethernet connection stop blinking. > 4. Serial terminal is still working, but after running a couple of commands it also freezes. If I try to run > cyclictest on serial in that case it mostly freezes immediately, but a couple of times it ran and displayed > that a couple of kernel are unavailable and after some time also froze. > > If I run cyclictest on serial connection it also freezes regardless if WiFi or Ethernet are connected. > > If I run “sudo cyclictest --smp -p49 -m” it does not freeze. So seems like it’s only affected when you > run something with priority equal or higher than the priority of peripheral interrupt handlers. > > Even though affinity mask for peripheral interrupts shows “f” it seems that they all run on cpu0 by > checking /proc/interrupts. I tried adding “isolcpus=0” to /boot/cmdline.txt and with it the > kernel does not freeze on “sudo cyclictest --smp -p51 -m” anymore. But it still freezes occasionally > while working, it just takes much longer now to catch the freeze (30-60 minutes). > > I’m trying to understand what causes such behaviour, as most of the drivers for Raspberry Pi 1 and 2 are the > same. I’ve ruled out mmc by completely disabling it in the kernel and running from USB flash. > > Any ideas what can be done to understand what is causing this? > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo <at> vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Hello Mikhaïl, I have the same issue, let me now if you find anything.��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
