msperl

BTW: with this test you have been mentioning that introduced "jitter" on USB audio - did that user also have the HDMI output running? I wonder because the way I...

OK - got it working with DT alone here the things I needed to make the DT work on the 4.0rc3 kernel: ``` &gpio { brcm,pins = ; brcm,function =...

BTW: the "simple" optimization to write as many bytes as possible immediately results in 64 bytes getting written, then you get an interrupt  It still means we spend...

yes - for very short request (total transfer time

Note that I have got now also patches for polling and filling the FIFO prior to enabling interrupts cutting down on latencies. I have also figured out that the spi_sync...

one other thing: would it not make sense to run the Command and Data as separate SPI-devices, where the core would schedule an extra GPIO up/down?

I have just received an USB Sound-card yesterday for testing the latency issues and I have to tell you that the card works with no jitter with the foundation kernel...

It is (at least on the RPI2 with 3.18.8-v7+): ``` root@rasp2:~# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 16: 0 0 0 0 ARMCTRL 16 bcm2708_fb dma 24: 1230 0 0...

Most other stuff got merged, so we can start address this - as soon as we reach 64 bytes this starts to make sense to use it...

Ok, i have started now on the dma implementation and have found a few things that may be of interest: A) my basic setup code is similar to what you...