[Intel-gfx] [PATCH] drm/i915: Print error state times relative to capture

[Chris Wilson]

Quoting Mika Kuoppala (2018-04-16 14:40:52)
> Using plain jiffies in error state output makes the output
> time differences relative to the current system time. This
> is wrong as it makes output time differences dependent
> of when the error state is printed rather than when it is
> captured.
> 
> Store capture jiffies into error state and use it
> when outputting the state to fix time differences output.

Good point. It was always confusing to see "several hours ago", when what
we wanted to know was how long before the hanging request. Hmm, do we want
to use that as our reference point rather than the capture timestamp? Do 
we even need to see the jiffies? (Yes, we probably do want the raw value
to check, but I think it's secondary.)

> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Please do consider using the (earliest) guilty timestamp as time 0 and
print before/after. If no guilty then use capture?
-Chris