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:
CONFIG_DMA_API_DEBUG=y
CONFIG_DEBUG_FS=y
CONFIG_DMA_API_DEBUG_SG=y
CONFIG_DMA_API_DEBUG_FENCE=y
CONFIG_DMA_API_DEBUG_EVENTS=y
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?
