[PATCH 1/3] drm/i915: Initialize pm_intr_keep during intel_irq_init for GuC

[Chris Wilson]

On Tue, Jan 17, 2017 at 04:09:26PM +0530, Sagar Arun Kamble wrote:
> Driver needs to ensure that it doesn't mask the PM interrupts, which are
> unmasked/needed by GuC firmware. For that, Driver maintains a bitmask of
> interrupts to be kept unmasked, pm_intr_keep.
> 
> pm_intr_keep was determined across GuC load. GuC gets loaded in different
> scenarios and it is not going to change the pm_intr_keep so this patch
> moves its setup to intel_irq_init.
> 
> This patch fixes incorrect RPS masking and solves bunch of SKL GT3
> performance regressions as Host RPS was taking frequency down when GuC is
> enabled. This was happening due to signed last_adj that becomes negative
> after 32 UP interrupts and makes cur_freq=min starting the ramp again.
> Next patch in the series avoids such frequency transitions.
> 
> Cc: Szwichtenberg, Radoslaw <radoslaw.szwichtenberg at intel.com>
> Cc: Tomi Sarvela <tomi.p.sarvela at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97017
> Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
s/Signed-off-by/Reviewed-by/
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre