PFIFO: command submission to execution engines

Contents:

• FIFO overview
• PIO submission to FIFOs
• DMA submission to FIFOs on NV4
• Puller - handling of submitted commands by FIFO
• NV1:NV4 PFIFO engine
• NV4:G80 PFIFO engine
• Tesla PFIFO engine
• GF100+ PFIFO engine
• GF100+ PSPOON engines
• PCOPY copying engine