#10045 HIGH 1.5-sof: XO-1.5 Record audio/video are out of sync with each other

[Daniel Drake]

On 11 May 2010 04:19, James Cameron <quozl at laptop.org> wrote:
> On Mon, May 10, 2010 at 11:14:33PM -0400, Martin Langhoff wrote:
>> You're definitely onto something there. Do old images with earlier
>> kernels show the problem? IOWs is there a reasonable starting point
>> for a bisection?
>
> Sorry, no.  This symptom has been with us always.  Some writes just
> take a long time, for no obvious reason.
>
> I spent some time testing write of 262144000 zero bytes to various
> media and filesystems, measuring the time for the write, time for the
> sync, and noting the top few write(2) syscall latencies.

I previously went even deeper:
http://dev.laptop.org/ticket/9688

I confirmed that the problem exists at the SDHCI level. Sometimes you
ask it to write 1kb and then you have to wait up to 600ms for the
completion interrupt to arrive.

Daniel