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bebe35bb73
I still have some Soekris net4826 in a Community Wireless Network I volunteer with. These devices use an AMD SC1100 SoC. I am running OpenWrt on them, which uses a patched kernel, that naturally has evolved over time. I haven't updated the ones in the field in a number of years (circa 2017), but have one in a test bed, where I have intermittently tried out test builds. A few years ago, I noticed some trouble, particularly when "warm booting", that is, doing a reboot without removing power, and noticed the device was hanging after the kernel message: [ 0.081615] Working around Cyrix MediaGX virtual DMA bugs. If I removed power and then restarted, it would boot fine, continuing through the message above, thusly: [ 0.081615] Working around Cyrix MediaGX virtual DMA bugs. [ 0.090076] Enable Memory-Write-back mode on Cyrix/NSC processor. [ 0.100000] Enable Memory access reorder on Cyrix/NSC processor. [ 0.100070] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0 [ 0.110058] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0 [ 0.120037] CPU: NSC Geode(TM) Integrated Processor by National Semi (family: 0x5, model: 0x9, stepping: 0x1) [...] In order to continue using modern tools, like ssh, to interact with the software on these old devices, I need modern builds of the OpenWrt firmware on the devices. I confirmed that the warm boot hang was still an issue in modern OpenWrt builds (currently using a patched linux v6.6.65). Last night, I decided it was time to get to the bottom of the warm boot hang, and began bisecting. From preserved builds, I narrowed down the bisection window from late February to late May 2019. During this period, the OpenWrt builds were using 4.14.x. I was able to build using period-correct Ubuntu 18.04.6. After a number of bisection iterations, I identified a kernel bump from 4.14.112 to 4.14.113 as the commit that introduced the warm boot hang. |
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| .. | ||
| mce | ||
| microcode | ||
| mtrr | ||
| resctrl | ||
| sgx | ||
| .gitignore | ||
| acrn.c | ||
| amd.c | ||
| aperfmperf.c | ||
| bugs.c | ||
| bus_lock.c | ||
| cacheinfo.c | ||
| centaur.c | ||
| common.c | ||
| cpu.h | ||
| cpuid-deps.c | ||
| cyrix.c | ||
| debugfs.c | ||
| feat_ctl.c | ||
| hygon.c | ||
| hypervisor.c | ||
| intel_epb.c | ||
| intel.c | ||
| Makefile | ||
| match.c | ||
| mkcapflags.sh | ||
| mshyperv.c | ||
| perfctr-watchdog.c | ||
| powerflags.c | ||
| proc.c | ||
| rdrand.c | ||
| scattered.c | ||
| topology_amd.c | ||
| topology_common.c | ||
| topology_ext.c | ||
| topology.c | ||
| topology.h | ||
| transmeta.c | ||
| tsx.c | ||
| umc.c | ||
| umwait.c | ||
| vmware.c | ||
| vortex.c | ||
| zhaoxin.c | ||