Re: [Question] Missing data after DMA read transfer

[Nicolas Morey-Chaisemartin]

Le 04/21/2016 à 10:35 AM, One Thousand Gnomes a écrit :
>> But if I try to copy_from_user (using the address coming from userland, the one passed to get_user_pages), the data has not been written and I see the memset value.
>>
>> I manage to build a test case that fails all the time, but never at the same offset within the buffer.
>> It's always in the middle (never at the start nor end), for a few pages long (varies between runs).
> Always page aligned, always cache line aligned or arbitrarily aligned ?
>
> Alan
It's always page aligned for both start and end (meaning last "untransferred" byte is the last byte of a page)

Nicolas