Bosi Daniele wrote: > I'm working on a DaVinci DM365 DVR board with a ARM926EJ-S rev 5 > (v5l) processor. My kernel version is "Linux version > 2.6.18_pro500-davinci_evm-arm_v5t_le" from dvsdk_2_10_01_18. My > application needs to acquire data from outside and read them with a > resolution of 1 msec. I know that the kernel I'm using is not a Real > Time Kernel, so I'm writing to know if someone had ever patched the > TI kernel to make it real time. > > I googled a little bit and I found people suggesting RTAI patch. I > downloaded it but it doesn't seem to have support for dm365 > architecture. Other ones suggest the Vanilla kernel... > > Any suggestion?
Xenomai? It is based on the Adeos I-pipe patch which has support for several ARM SOCs. It integrates the FCSE patch, which allows reducing latencies on armv4/armv5 processors. Xenomai also has a guide explaining you how to port on a new ARM SOC. The website: http://www.xenomai.org The ARM I-pipe porting guide: http://www.xenomai.org/index.php/I-pipe:ArmPorting With some experience, a port to a new ARM SOC takes about 1 or 2 days, including the time to debug/validate it. Note however that you will have to upgrade your kernel to a more recent version. Please note that Xenomai is based on the same approach as RTAI (running a second real-time kernel besides linux), which make things a little harder from the drivers point of view: all drivers which need to be used with real-time guarantees need to be ported to the real-time kernel. The other solution is the "preempt_rt" patch, which does not need a second kernel, can use Linux drivers, but, at least on ARM does not get latencies as low as Xenomai. A comparison between Xenomai and preempt_rt on omap3 was published some time ago: https://www.osadl.org/fileadmin/dam/rtlws/12/Brown.pdf Another paper on the "preempt_rt" patch advise not using it on ARMv5 with a cycle time of 1ms (decision diagram on the last page): http://lwn.net/images/conf/rtlws11/papers/proc/p11.pdf Regards. -- Gilles Chanteperdrix _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
