hi all:
for iso transactions, we use below function to calculate trbs
addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
td_len = urb->iso_frame_desc[i].length;
num_trbs = DIV_ROUND_UP(td_len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
TRB_MAX_BUFF_SIZE);
Could we use below method to calculate it instead?
addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
td_len = urb->iso_frame_desc[i].length;
- num_trbs = DIV_ROUND_UP(td_len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
TRB_MAX_BUFF_SIZE);
+ num_trbs = DIV_ROUND_UP(td_len ,TRB_MAX_BUFF_SIZE);
Why the trb calculation for iso is related to dma address?
Appreciate your kind help in advance,
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