Improved kernel module - Githubissues

matteoserva commented 4 months ago

Using cyclic dma for data transfer
removed kernel threads. Now everything done in callbacks
keeping multiple transactions running to avoid delays
discarding data if too late
logging the module performance
cleaned out the code
modified communication with userspace to fix polling
removed redundant locks
changed buffers behavior to improve efficiency
fixed compatibility with latest raspbian kernel

meexmachina commented 3 months ago

Thats an amazing work! Way beyond my knowledge and capability. Bravo! pulled it yesterday and started to review it (build, test). It has a few issues I noticed that we need to fix:

every few "stream start/end" cycles, when we end the stream, there is a kernel oops. I suspect that *inst is NULL for some reason and the 'smi_is_active' function gets a null dereference.
the low channel doesn't start consistently (sometimes it starts) and I notices it is starting only when SMIL is larger than zero (as printed out by "print_smil_registers_ext("init 5");"
When we start the high channel first and then switch to the low channel the stream runs. Thanks a lot, great work!

matteoserva commented 3 months ago

I pushed a commit and fixed problem 2 and 3.

Could you send me the full kernel message when you see the oops? I cannot reproduce it here and I need at least the stack trace.
Right now I'm running the software on a raspberry pi zero 2W with raspbian bookworm. What is your setup? Thanks

meexmachina commented 3 months ago

Did testing and it looks great. I merge it now..

cariboulabs / cariboulite

Improved kernel module #192