The journey into spi & dma.. So for awhile now, we've had a bug for spi users, where the system would hardlock at the "160" byte threashold:
debian@beaglebone:~$ sudo dd if=/dev/zero of=/dev/spidev1.0 bs=159 count=1 1+0 records in 1+0 records out 159 bytes (159 B) copied, 0.000508833 s, 312 kB/s debian@beaglebone:/sys$ dd if=/dev/zero of=/dev/spidev1.0 bs=160 count=1 ^C (hangs..) "160" happens to be a the magic number where DMA takes over from PIO mode... Well as of yesterday: debian@beaglebone:~$ sudo dd if=/dev/zero of=/dev/spidev1.0 bs=320 count=1 1+0 records in 1+0 records out 320 bytes (320 B) copied, 0.00266366 s, 120 kB/s So here's the deal, it looks to be a spi/overlay bug, as we don't seem to get the correct dma tx/rx channels.. What interesting, when the "spi" node is enabled in the main dtb: https://github.com/RobertCNelson/dtb-rebuilder/blob/4.1-ti/src/arm/am335x-boneblack-spi0.dts#L120-L137 it works fine in dma mode... So with "4.1.12-ti-r27" spi-dma is now disabled.. *btw: Late last night i wrote a better fix (will be r28) where you can disable "spi-dma" via the dt option: ti,pio-mode; https://github.com/beagleboard/bb.org-overlays/commit/48d33d4d22f284103db83626b343724cf18c578d Regards, -- Robert Nelson https://rcn-ee.com/ -- 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.
