On Tuesday 09 July 2013 09:29:50 WangChen wrote:
Hi,
> Sorry, I still have not understood why we need to get the var - available by
> "dev->bulk_in_filled - dev->bulk_in_copied". dev->bulk_in_copied is always
> reset as zero in skel_do_read_io, right?
Well, no. If skel_do_read_io() runs, it is zero. But there's no guarantee that
skel_do_read_io() runs.
> So when we go to line 289, I think it happens after read callback returns,
maybe
> and at that time, bulk_in_copied should have been set as zero. Though I see
> at line 315, bulk_in_copied is given new data, but it will be reset to zero
> in next retry - skel_do_read_io, right?
Only if no data is left. Otherwise no new IO is triggered.
> Maybe I have not understood the reset case you mentioned makes me can not
> reach your idea.
> For the case there may be data left from the last read, I have the same
> quesiton. I don't know what the bulk_in_copied is used for. Maybe I have to
> do some more practice test to see how these codes work.
You need to know which part of the buffer is already used up.
Regards
Oliver
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