On Friday, January 16, 2015 at 5:34:29 PM UTC+2, RobertCNelson wrote: > > On Fri, Jan 16, 2015 at 2:53 AM, <[email protected] <javascript:>> > wrote: > > Hi, > > > > I have a simple C program which writes something to a serial port and > then > > reads an answer, every 5 ms or so. I'm using an FTDI USB-to-RS232 > adapter > > connected to BBB at 115200 bps. In 3.8.13-bone63 this works fine, but > there > > are some reasons I need to use a later kernel. I upgraded to the > > 3.14.22-ti-r31 kernel, where my program freezes the user space > completely > > after a couple of seconds. Unplugging the USB adapter makes everything > run > > again (but of course my program closes since the serial port is no > longer > > there). Nothing special in dmesg. I then upgraded to 3.14.26-ti-r43, > where > > the problem is slightly different, appearing after several minutes to an > > hour or so, and not freezing completely, making everything just > incredibly > > slow (softirq's use about 70 % of CPU time according to top). Closing my > > program brings everything back to normal. Then I tried 3.18.2-bone1, > where > > it works again correctly. > > > > I see that bone-kernels have DMA disabled in USB, but I also tried > use_dma=0 > > module parameter with 3.14.26-ti-r43 and it didn't help. I'd use 3.18.2, > but > > unfortunately dtb-rebuilder doesn't have a branch for that kernel, and I > > need to modify the GPIO's a little. The .dtb-file for 3.14.26 doesn't > boot > > with 3.18.2. > > > > So, > > 1) Is there something I could try to make it work on 3.14-ti kernels? > > Disable: > CONFIG_USB_TI_CPPI41_DMA > > Enable: > CONFIG_MUSB_PIO_ONLY >
I'll try these if I have the need to go back to 3.14-series. > > > 2) Is there an easy way to create a custom dtb for the 3.18-bone > kernels? > > Use the v3.19.x branch: > > https://github.com/RobertCNelson/dtb-rebuilder/tree/3.19.x > > Thanks, this helped! Now I'm running happily with 3.18.2-bone1. Matti -- 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]. For more options, visit https://groups.google.com/d/optout.
