Hello, our team develops a Linux-based embedded system to realise a programmable logic controller. So we investigate several possibilities to augment Linux real-time capabilities. Naturally, the PREEMPT_RT-patch is interesting. I searched the wiki, the mailing list archive, listened to Mr. Assmann's talk at the Chemnitz Linux Days 2010 and read the corresponding chapter in "Building Embedded Linux Systems" by Karim Yaghmour. Nevertheless, I have a question to makes thinks clear once and for all: Does the priority inheritance mechanism work without using special (Pthread-) mutexes in userspace? (As far as I understood, it does not.) Imagine a hypothetical case: a high RT-priority (60) task triggers a synchronous/blocking system call which triggers a device driver whose ISR is a kernel thread with RT-priority 49. So, a medium RT-priority (55) task may block the high RT-priority task, doesn't it? With kind regards, Martin Daeumler -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
