[Intel-gfx] [PATCH 13/18] drm/i915: remove too-frequent FBC debug message

[Zanoni, Paulo R]

Em Qua, 2015-10-21 às 14:01 +0100, Chris Wilson escreveu:
> On Tue, Oct 20, 2015 at 11:49:59AM -0200, Paulo Zanoni wrote:
> > If we run igt/kms_frontbuffer_tracking, this message will appear
> > thousands of times, eating a significant part of our dmesg buffer.
> > It's part of the expected FBC behavior, so let's just silence it.
> > 
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Looks fine. Out of curiosity what metrics do we have for FBC
> activity? I
> presume we have tracepoints for activate/deactivate. and perhaps a sw
> timer, and a hw debug register?

The most important metric is PC state residency, but that requires the
machine to be properly configured: if SATA is preventing our machine
from going deeper than PC3, FBC won't change PC state residencies.
Also, our public processor datasheet docs mention the maximum expected
PC states for the most common screen resolutions.

We can work on adding more things later, such as the tracepoints or
software timer you mentioned. I've been 100% focused on getting the
bugs out first. Is there anything specific you think you could use?

> -Chris
>