drm/i915: Set adjustment to zero on Up/Down interrupts if freq is already max/min
authorSagar Arun Kamble <sagar.a.kamble@intel.com>
Fri, 20 Jan 2017 03:48:24 +0000 (09:18 +0530)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 20 Jan 2017 09:32:47 +0000 (09:32 +0000)
commit7e79a6836cfd1bac20e2be3fafdc3caca27c9d69
tree4822ce51525e1316362e0e5c12b033e627b99ea3
parente96128235b0fbddff1228b37033077397dbd21d9
drm/i915: Set adjustment to zero on Up/Down interrupts if freq is already max/min

When we reach the user's RPS limits, stop requesting an adjustment. Even
though we will clamp the requested frequency later, we rely on interrupt
masking to disable further adjustments in the same direction. Even
though it is unlikely (one scenario is a bug in the driver, another is
careful manipulation through the uAPI) if we keep exponentially
increasing the adjustment value, it will wrap and cause a negative
adjustment.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484884104-28134-2-git-send-email-sagar.a.kamble@intel.com
drivers/gpu/drm/i915/i915_irq.c