Hi Johannes, On 07/25/2017 08:54 AM, Johannes Kliemann wrote: > Hi, > > I'm currently writing a dde_linux driver that requires to wait for an > interrupt to be handled. > It basically initializes the hardware and then waits for an event to > occur. This event is usually triggered by the interrupt (respectively > its handler) which occurs after hardware initialization. > My problem is that this interrupt doesn't appear while the function > triggering it didn't return. So when this function blocks to wait for > the interrupt, a deadlock is created. Besides using the timer I tried to > block the execution with a semaphore creating the same problem. > Creating an async version is no option due to the architecture of the > Linux driver. > > How are interrupts handled in this case? What causes them to block and > how can I work around this? >
If I gather your description correctly, you are executing Linux code from the entrypoint context. If this code somehow blocks, lets say by calling 'wait_event_interruptible' or something else, the EP cannot receive signals, and therefore no interrupts. The solution to this problem are 'Lx::Task'(s). All Linux code should be executed by these tasks, which are able to block and can be unblocked by the EP upon signal reception. A small example can be found under 'dde_linux/src/drivers/framebuffer/intel/main.cc', there the Linux code is executed by a task in 'run_linux', which is woken up by the 'Policy_agent' signal handler. Regards, Sebastian P.S. I hope you are porting a driver and not writing one from scratch ;) -- Sebastian Sumpf Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
