> On Jun 10, 2019, at 7:36 PM, Robert Heller <[email protected]> wrote: > > At Mon, 10 Jun 2019 18:29:33 -0400 Daniel Kulp <[email protected] > <mailto:[email protected]>> wrote: >> >> “bone kernel” >> >> That’s important. The TI kernels are not usable for my application. I >> need to use the bone kernel. (At least for the 4.9 and 4.14 series… >> haven’t had time to test with the TI 4.19 series kernels) > > Ah. I see. What sorts of differences are there between the TI kernels and > the Bone kernels? Is there some reason the Bone don't have the MCP23S08 > module enabled? Wondering if a bug/feature request might make sense…
Honestly, I have no idea what the “official” differences are and why some modules are available in one and not the other. Likely just someone requested something. At some point, a “diff” of the configs and unifying the optional modules of it may make sense, not really sure. In my particular case, I *believe* the power management stuff that is in the TI kernel is screwing up the timing to access anything in the L4_WKUP interconnect (which includes GPIO0). For folks that value the power management stuff, the TI kernel is much better. It contains the cpu IDLE driver and a bunch of other things that allow it to lower the power usage. In my case, I don’t care about any of that. Even with the bone kernel, I lock the CPU at 1ghz. I need more predictable and consistent access to the gpio pins (all of them). With the TI kernel, access to GPIO1-3 (via the PRU) is very consistent, but access to GPIO0 can have several hundred ns delays which I cannot have (relatively infrequent, once or twice a second, but still too often). I KNOW the CPU idle stuff in the TI kernel plays a large part of the problem. If I use cpupower to turn off the idle states, 90% of the delays go away (so once every 10 seconds or so). Anyway, the bone kernel doesn’t have a bunch of the PM things so I don’t see any of the issues with it. Of course, it might not be PM at all. Could be something else completely different between the kernels. -- Daniel Kulp [email protected] <mailto:[email protected]> - http://dankulp.com/blog <http://dankulp.com/blog> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/6F907568-CC97-42FA-BBBC-E84C28203ADD%40kulp.com. For more options, visit https://groups.google.com/d/optout.
