I am currently working on some PCI-e device stuff, that requires me to get the trace for DMA transactions on a specific (say GPU or NIC ) PCI card. After doing some research I found a useful post by xealits, but it seems doesn't tell how many bytes are read/written in a certain DMA transaction. I then found a kernel module named dma_debug may fully meet my expectations

I tried to recompile kernel v6.7 with configure options:


and add dma_debug.debug_dma=1 to grub default booting variables. But unfortunately, dmesg seems completely identical to when booting the old kernel. Also, dma_debug didn't show up in /sys/kernel/debug.

Am I missing something? How can I get the dma_debug to work? If this module is deprecated, is there any substitute method?


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