Stan, While some of the changes from the rt-preempt patches have made their way upstream, the majority of the modifications have not made it into the mainline kernel. With the rt-preempt patchset, nearly everything in the kernel is preemptible, interrupts run in software context with priorities (making them preemptible), this is what you need if you want true real-time latencies.
If you want to try patching the 2.6.26-davinci1 kernel with the relevant rt-preempt patchset, we could try to work together in getting it working fully. With the changes I documented in the post below, I was able to get the kernel running when compiled with the Montavista toolchain. http://linux.omap.com/pipermail/davinci-linux-open-source/2008-August/007853 .html Kernel 2.6.23 is known to be working fully with the rt patchset, look at Dirk's post here: http://linux.omap.com/pipermail/davinci-linux-open-source/2007-October/00428 3.html Thanks, Ali From: Stankiewicz Bredkjaer [mailto:[EMAIL PROTECTED] Sent: Tuesday, September 02, 2008 5:00 AM To: Ali Asgar Sohanghpurwala Subject: Re: rt-preempt on linux-davinci 2.6.26 Ali, Yet another dumb question, I have read somewhere that the Real Time preempt patch is already included in new kernels (2.6.26 and so on). Or are you talking about a special one? Since I would like to use the Real time functionalities for some experiments on the DM6467 board, i would be pleased to know if it is not the case. Regards Stan. --- On Tue, 9/2/08, Ali Asgar Sohanghpurwala <[EMAIL PROTECTED]> wrote: From: Ali Asgar Sohanghpurwala <[EMAIL PROTECTED]> Subject: Re: rt-preempt on linux-davinci 2.6.26 To: "Dirk Behme" <[EMAIL PROTECTED]> Cc: [email protected] Date: Tuesday, September 2, 2008, 9:35 AM On Sat, 2008-08-30 at 06:47 +0200, Dirk Behme wrote: > > Can you send us output of arm-...-gcc -v to get an idea what > toolchains you use? Can you try with CodeSourcery's 2007q3-51 ARM > GNU/Linux tool chain > > http://www.codesourcery.com/gnu_toolchains/arm/portal/release313 > > ? > > This is known to build working kernels (if not using -Os). If you have > your ethernet issue with this, too, I would look for a code issue. > > Thanks > > Dirk Dirk here is the output from running -v on the Montavista Toolset (which creates a working 2.6.26-davinci1-rt1 kernel with my wrong_size_cmpxchg hack): Reading specs from /opt/mv_pro_4.0/montavista/pro/devkit/arm/v5t_le/bin/../lib/gcc/armv5tl-mont avista-linuxeabi/3.4.3/specs Configured with: ../configure --host=i686-pc-linux-gnu --target=armv5tl-montavista-linuxeabi --prefix=/opt/montavista/foundation/devkit/arm/v5t_le --exec-prefix=/opt/montavista/foundation/devkit/arm/v5t_le --bindir=/opt/montavista/foundation/devkit/arm/v5t_le/bin --sbindir=/opt/montavista/foundation/devkit/arm/v5t_le/sbin --sysconfdir=/opt/montavista/foundation/devkit/arm/v5t_le/etc --datadir=/opt/montavista/foundation/devkit/arm/v5t_le/share --includedir=/opt/montavista/foundation/devkit/arm/v5t_le/include --libdir=/opt/montavista/foundation/devkit/arm/v5t_le/lib --libexecdir=/opt/montavista/foundation/devkit/arm/v5t_le/libexec --localstatedir=/opt/montavista/foundation/devkit/arm/v5t_le/var --sharedstatedir=/opt/montavista/foundation/devkit/arm/v5t_le/share --mandir=/opt/montavista/foundation/devkit/arm/v5t_le/man --infodir=/opt/montavista/foundation/devkit/arm/v5t_le/info --build=i686-pc-linux-gnu --program-transform-name=s,^,arm_v5t_le-, --enable-cross --with-sysroot=/opt/montavista/foundation/devkit/arm/v5t_le/target --enable-shared --enable-languages=c,c++ --enable-__cxa_atexit --enable-threads=posix --disable-multilib --with-gxx-include-dir= ${prefix}/lib/gcc/armv5tl-montavista-linuxeabi/3.4.3/../../../../target/usr/ include/c++/3.4.3 --with-numa-policy=yes --with-float=soft --with-cpu=arm10tdmi --with-interwork --with-arch=armv5t --with-tune=arm10tdmi --libexecdir=/opt/montavista/foundation/devkit/arm/v5t_le/lib Thread model: posix gcc version 3.4.3 (MontaVista 3.4.3-25.0.30.0501131 2005-07-23) Here is the output from the 2007q3 CodeSourcery Toolchain: Using built-in specs. Target: arm-none-linux-gnueabi Configured with: /scratch/paul/lite/linux/src/gcc-4.2/configure --build=i686-pc-linux-gnu --host=i686-pc-linux-gnu --target=arm-none-linux-gnueabi --enable-threads --disable-libmudflap --disable-libssp --disable-libgomp --disable-libstdcxx-pch --with-gnu-as --with-gnu-ld --enable-languages=c,c++ --enable-shared --enable-symvers=gnu --enable-__cxa_atexit --with-pkgversion=CodeSourcery Sourcery G++ Lite 2007q3-51 --with-bugurl=https://support.codesourcery.com/GNUToolchain/ --disable-nls --prefix=/opt/codesourcery --with-sysroot=/opt/codesourcery/arm-none-linux-gnueabi/libc --with-build-sysroot=/scratch/paul/lite/linux/install/arm-none-linux-gnueabi /libc --enable-poison-system-directories --with-build-time-tools=/scratch/paul/lite/linux/install/arm-none-linux-gnue abi/bin --with-build-time-tools=/scratch/paul/lite/linux/install/arm-none-linux-gnue abi/bin Thread model: posix gcc version 4.2.1 (CodeSourcery Sourcery G++ Lite 2007q3-51) I turned off CC_OPTIMIZE_FOR_SIZE (which would otherwise compile with -Os on), and still no luck. _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
_______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
