Are you running a real time OS on the Pi 3? Sorry to ask I just can't keep details of your project in my head. What you are describing sound like you might be. Seems lie whatever software runs in Kernal mode is being a "hog" and running for more than a microsecond with interrupts disabled, suffering like that really messes with software other than the hog.
I used to like to use slow computers to test my software because this problems showed up. Tossing a gross over kill of raw cpu power many times fixes where one driver or real time task is not being nice to others. I saw simmons like your MANY times going back to my days as a device driver writer on CDC mainframe computers. I wrote driver for a printer multiplexer (the allowed an old line printer to connect to up to four different mainframes and it works real well but almost NOTHING else works on the our big machines. My driver was using $24M worth of hardware to spin and wait on a bit. THAT is the type of thing I bet is going on. Some privileged task is hogging the CPU. This does not happen in a normal non-real time OS unless you have a buggy device driver (as these run in Kernel mode. The "correct' way to implement real time is to ONLY do the minimum you need to in the privileged mode and if more work or some calculation needs to be done. You put an entry on a work queue and a user mode task reads the queue, In short problem is simtomatic of the bugs that are common in real time systems. Especially RT system with a significant computational load on them. Hangs, missed interrupts and so on. Debufgging is hard, you end up doing stuff like writing debug messages by toggling a GPIO pin and watching for the toggle with a logic analyzer. My method now days is to never even try. I run the real-time stuff on a micro controller running an RTOS and the higher level stuff on a Pi3 or PC running Linux. On Wed, May 10, 2017 at 5:49 PM, Gene Heskett <ghesk...@shentel.net> wrote: > Greetings all; > > Detective stuffs, electronically, have always been my specialty. But I > have one now that is a bit of a puzzle even for me. > > First, I mesaflash verified all 3 of my 7i90's. > > Then I hung them on the pi, and all of them returned the error I have > posted quite a few times already. > > So I ordered that up-board. In the meantime I am less than ecstatic > about that 1366x768 monitor, so I hit wallies and found a 1920x1080 AOC > that the sales type said had an hdmi input. $88, so it followed me home. > > On unpacking I noted two things, first being that its power supply was a > wall wart that plugged into the usual round socket on the bottom of the > interface ridge on the back. 2nd was that DVI was the best input it > had, requiring an hdmi to DVI adapter be inserted and screwed down, and > the hdmi plugged into that. > > Mounted it where the other 1366x768 had been hanging, discovering the > arm's bracket nicely covered the I/O shelf, making it quite difficult to > get things plugged in and screwed down. > > Several hours later I finally got /boot/config.txt configured so it ran > at its 1920x1080 rated resolution. Looked good. Tried linuxcnc, and > darned if it didn't run normally once I had taken a pin reference to a > units pin back out. No biggie, that card didn't have that module on it. > > So now I am wondering if the old, bastard 1366x768 rated monitor was > somehow grabbing a gpio pin and mucking things up by interfering with > the SPI buss. > > Am I on the right track, or barking at the moon? Discussion please. > > In the FWIW category, the 3 adapters I made, using the OSHPark 40 pin to > 26 pin board with the 3 88 ohm terminator resistors, which because there > were not any 88 ohm r's at digikey, so mine are 86.7 ohms. None of them > work at all. They all return: > > 00000000 00000000 00000000 00000000 when queried for the boards id. > > My home made cable is the only one that works, about 8" of overall > length. > > The very poor keyboard and mouse response continues unabated. This is > regardless of the cpu load. Reboot it. 3 out of 4 times that will fix > it for a while, 4th time its even worse. Misses key up events, so it > goes into the autorepeat until another key is tapped. Hit backspace to > get rid of the unwanted characters and the backspace goes into > autorepeat. nano or geany makes no difference. Changing keyboards has > no effect. > > I don't have the machine moving yet, when I decided to test ALL the > 7i90's I had, I ripped stuff off the 50 pin sockets w/o drawing a map, > so now I am tracing down each wire in turn, and plugging it back into > the 7i90 by looking up that items function in my .hal files. That and > because many weren't in a connector housing, and I want to rectify that, > I tried to glue up 2 and a half of the 2x10 styles, but apparently the > latest and greatest in super glues is not up to butt gluing these > things, it breaks VERY easily. Made more difficult because there are > not any Mesa 7i42TA's in the states and I want to get three of them to > serve as static voltage absorber's to protect the ultra sensitive 7i90 > outputs. Not to mention that it will make the hookup buckets neater. > > And wasted the afternoon getting the 1st of a 3 shot series under my left > kneecap. And Dee, who watches the news, says we are supposed to get > around 2.5" additional rain over the next 2 days. I wish humans could > hibernate... Sometimes I try, but I still have recycle the water. :) > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
