From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4D3E4EBA.6050806@domain.hid> Date: Tue, 25 Jan 2011 05:16:58 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4D3E385A.5010209@domain.hid> <4D3E42BA.4000601@domain.hid> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Segmentation Fault when writing in registers (AT91SAM - ARM9) List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: at91_enthus Cc: xenomai-help at91_enthus wrote: > On Mon, Jan 24, 2011 at 9:25 PM, Gilles Chanteperdrix < > gilles.chanteperdrix@xenomai.org> wrote: > >> at91_enthus wrote: >>> On Mon, Jan 24, 2011 at 8:41 PM, Gilles Chanteperdrix < >>> gilles.chanteperdrix@xenomai.org> wrote: >>> >>>> at91_enthus wrote: >>>>> Hi. >>>>> >>>>> I was testing Xenomai on my AT91SAM9G20-based board and tried to adapt >>>> the >>>>> code found here: >>>>> http://www.armadeus.com/wiki/index.php?title=Xenomai:Blinking_LEDs . >>>> By the way, this code is ridiculous. It creates a real-time task to >>>> write to some non real-time device, which makes the real-time task >> useless. >>>> >>> I know. >> Yes, but this example is bad in many ways: >> - first it uses xenomai api to create a real-time task, and uses write >> which causes the real-time task to switch to secondary domain; >> - the Makefile does not use xeno-config, which have been the recommended >> way of getting the compiler flags since day 1; >> - it nullifies SIGTERM and SIGINT, which is a dubious decision, and >> could lead people to believe that they should do the same when using >> Xenomai, whereas there is no such requirement. >> - the pointers point to outdated version of the documentation. >> - it uses runinfo/xeno-load, which are kind of outdated too, make things >> uselessly complicated, and in any case, tell you to type Ctrl-C to >> interrupt the program, which is bound to fail if anything goes wrong, >> since SIGINT is neutralized in the program. >> >>> That's why I went to mmap(). >> That is not really the right solution either. I admit that for driving >> leds, it may be a bit overkill, but anyway, what you should do is write >> an RTDM driver for driving the leds. Keeping the driver separated from >> the application will allow the same program to run on other platforms >> where driving the LEDS is done differently without changing much of the >> application code. In other word, the application/driver separation is a >> sane one. >> >> Anyway, mmap should work. >> >> (I chose that sample code because, for >>> now, I am only learning to use basic functions) >>>> Wrong test here. Should be "if (aic_base == MAP_FAILED)" >>> Indeed, my program fails miserably when I check the mapping of AIC, not >>> PIOB's. And yet, I just can't figure why in the non-Xenomai code, AIC >>> mmap-ing works fine. >> Well errno might give you a clue. Do you have FCSE enabled? >> >> Regards. >> >> -- >> Gilles. >> > > FCSE is enabled. errno returns 22 (invalid argument). best effort or guaranteed? Please activate FCSE messages. How big is MAP_SIZE? -- Gilles.