Re: [PATCH 4.19 21/38] spi: fsl-espi: Only process interrupts for expected events

[Chris Packham]

On 7/10/20 8:36 am, Pavel Machek wrote:
> Hi!
>
>> [ Upstream commit b867eef4cf548cd9541225aadcdcee644669b9e1 ]
>>
>> The SPIE register contains counts for the TX FIFO so any time the irq
>> handler was invoked we would attempt to process the RX/TX fifos. Use the
>> SPIM value to mask the events so that we only process interrupts that
>> were expected.
>>
>> This was a latent issue exposed by commit 3282a3da25bd ("powerpc/64:
>> Implement soft interrupt replay in C").
> We don't seem to have commit 3282... in 4.19, so we don't need this
> one in 4.19-stable according to the changelog.
Technically 3282... exposed the issue by making it more likely to happen 
so 4.19 might just have a really low probability of seeing the issue (I 
think I did try reproducing it on kernels of that vintage). Personally 
I'm not too fussed the kernel versions I care about have the fix. Maybe 
someone from NXP cares enough to pursue it.