Hi Huacai > Hi, David, Lemote's pre-installed kernel uses exactly the same source > in http://dev.lemote.com/cgit/linux-official.git/, the only difference > is GCC, we use the cross-compiler which can be found here: > http://dev.lemote.com/files/resource/toolchain/cross-compile/
You were right, the toolchain may be the culprit here! Compiling kernel 3.5.0-8.lemote with the lemote gcc-4.5.2 toolchain [1], produces a kernel that works without problems. 3.5.0-2, 3.5.0-3, 3.5.0-5 also work when built with that toolchain. Just to make sure I also built 3.5.0-2, -3, -5 with my gcc-4.6.4 toolchain and all these kernels exhibit the same screen blanking problem I encountered before. Quite unbelievable. Then I tried to build my own toolchain using upstream gcc-4.5.4 from [2] and binutils 2.22 from [3]. Kernels built with this toolchain do work :) I wonder whether Lemote's gcc-4.6.4 [4] toolchain actually works. I cannot easily test it as these binaries require libc 2.14 which is unavailable under Debian Wheezy here. I tried to build my own toolchain matching the exact versioning as lemote (gcc-4.6.4 and binutils 2.22), but kernels compiled with that version do have the blank screen problem. Does lemote use any non-upstream version of GCC (linaro?) or any other patches? Where's the source corresponding to [1,4]? Maybe it's not even a GCC problem but just some interaction between kernel bugs and CPU errata (?) that are triggered by certain machine code sequences or code addresses that just happen to be output by my 4.6.4 toolchain? I think I also need to find out how to run the PMON RAM tester to rule out any issues caused by faulty memory. cheers, David [1] http://dev.lemote.com/files/resource/toolchain/cross-compile/cross-loongson-gcc4_5_2-binutils2_21.tar.bz2 [2] ftp://ftp.cs.tu-berlin.de/pub/gnu/gcc/ [3] ftp://ftp.cs.tu-berlin.de/pub/gnu/binutils/ [4] http://dev.lemote.com/files/resource/toolchain/cross-compile/x86_64_cross-loongson-gcc4_6_4-binutils2_22.tar.bz2 -- GnuPG public key: http://dvdkhlng.users.sourceforge.net/dk2.gpg Fingerprint: B63B 6AF2 4EEB F033 46F7 7F1D 935E 6F08 E457 205F
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