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SubjectRe: [PATCH] spi: dw: use "smp_mb()" to avoid sending spi data error
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On 2020/1/3 9:04, Mark Brown wrote:
> On Sat, Dec 28, 2019 at 04:31:53PM +0800, kongxinwei wrote:
>
>>> I'd be much more comfortable here if I understood what this was
>>> supposed to be syncing - what exactly gets flushed here and why
>>> is a memory barrier enough to ensure it's synced? A comment in
>>> the code would be especially good so anyone modifying the code
>>> understands this in future.
>
>> Because of out-of-order execution about some CPU architecture,
>> In this debug stage we find Completing spi interrupt enable ->
>> prodrucing TXEI interrupt -> running "interrupt_transfer" function
>> will prior to set "dw->rx and dws->rx_end" data, so it will result
>> in SPI sending error
>
> Could you update the commit message to say that, and ideally also
> add a comment saying something like "Ensure dw->rx and dw->rx_end
> are visible" please?
>
OK, i WILL update it.

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