[Intel-gfx] [PATCH 2/2] drm/i915: re-enable rc6 by default

[Eugeni Dodonov]

Most of the rc6-related hangs and major issues were addressed for the past
months.

Let's re-enable it by default to provide a more wider testing, and catch
the remaining problems.

According to tests, enablement of rc6 results in up to +50% improvements
in power usage and battery life, so it certainly would be a nice feature
to have enabled by default.

Also, most of the issues related to rc6 seem to came from VTd, so if you
are experiencing any problems with it, try disabling VTd in bios or using
intel_iommu=off kernel parameter to investigate whether it solves the
issue.

Acked-by: Keith Packard <keithp at keithp.com>
CC: Daniel Vetter <daniel.vetter at ffwll.ch>
CC: Jesse Barnes <jbarnes at virtuousgeek.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38567
Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 71f887a..f72f65d 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -63,7 +63,7 @@ module_param_named(semaphores, i915_semaphores, int, 0600);
 MODULE_PARM_DESC(semaphores,
 		"Use semaphores for inter-ring sync (default: true)");
 
-unsigned int i915_enable_rc6 __read_mostly = 0;
+unsigned int i915_enable_rc6 __read_mostly = 1;
 module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600);
 MODULE_PARM_DESC(i915_enable_rc6,
 		"Enable power-saving render C-state 6 (default: true)");
-- 
1.7.7.3