hi David and All:
>> > Because the trb buffers can't cross a 64k physical address boundary.
>>
>> Is it only specific to iso scheduling or bulk also need to take care?
>> from your kind explanation, the trb buffer for Bulk also need to take
>> care crossing 64k physical boundary.
>> But i don't find it for bulk transfer.
>> Below is excerpted from xhci_queue_bulk_tx
>> while (running_total < urb->transfer_buffer_length) {
>> num_trbs++;
>> running_total += TRB_MAX_BUFF_SIZE;
>> }
>
> Hmmm... that looks like a division by a power of 2!
I am not quite understand what you mean "a division by a power of 2"
Would you please give me more hint? ^^
> The constraint applies to all TRB.
i found where bulk handle 64k physical address boundary as you explain.
it just a couple lines ahead of the source code I captured in the
previous mail :P
Meanwhile, I have another question:
for iso transfer, the first iso trb cannot cross page boundary,
but I cannot find this restriction in xhci driver.
appreciate all your kind help,
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