drm/i915: disable LVDS downclock by default
Many platform support this feature, and it can provide significant
power savings when the reduced refresh rate is low. However, on some
platforms a secondary (reduced) timing is provided but not actually
supported by the hardware. This results in undesirable flicker at
runtime.
So disable the feature by default, but allow users to opt-in to the
reduced clock behavior with a new module parameter, lvds_downclock,
that can be set to 1 to enable the feature.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 66f7bac..46d8896 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -45,6 +45,9 @@
unsigned int i915_powersave = 1;
module_param_named(powersave, i915_powersave, int, 0400);
+unsigned int i915_lvds_downclock = 0;
+module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
+
static struct drm_driver driver;
#define INTEL_VGA_DEVICE(id, info) { \
