Re: [PATCH] spi: core: Increase timeout value

From: Harini Katakam
Date: Thu Apr 10 2014 - 23:10:04 EST


Hi Mark,

On Thu, Apr 10, 2014 at 11:06 PM, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Thu, Apr 10, 2014 at 06:20:29PM +0530, Harini Katakam wrote:
>
>> Considering acceptable latencies, this timeout can be set to a large
>> value >= 1*HZ typically.
>
>> This patch adds a tolerance of 2000 msec in the core accordingly.
>
> That's too much, it's 2 seconds which gets to be incredibly painful when
> trying to debug problems - if you're sitting there waiting for a driver
> to time out some operations (and it may be more than one of them) so you
> can look at the diagnostics it can be quite aggrivating. That's why the
> delays are related to the expected runtime for the operation. Something
> like double the expected runtime plus something in the 100ms or so range
> perhaps?
>

OK.

> Ideally we'd use the actual speed the device set rather than the
> requested one too, that'd help.

How would you propose to do that - driver should write back actual speed set
to xfer->speed_hz?

Regards,
Harini
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