From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> We currently only enter PC8+ after all its required conditions are met, there's no rendering, and we stay like that for at least 5 seconds. I chose "5 seconds" because this value is conservative and won't make us enter/leave PC8+ thousands of times after the screen is off: some desktop environments have applications that wake up and do rendering every 1-3 seconds, even when the screen is off and the machine is completely idle. But when I was testing my PC8+ patches I set the default value to 100ms so I could use the bad-behaving desktop environments to stress-test my patches. I also thought it would be a good idea to ask our power management team to test different values, but I'm pretty sure they would ask me for an easy way to change the timeout. So to help these 2 cases I decided to create an option that would make it easier to change the default value. I also expect people making specific products that use our driver could try to find the perfect timeout for them. Anyway, fixing the bad-behaving applications will always lead to better power savings than just changing the timeout value: you need to stop waking the Kernel, not quickly put it back to sleep again after you wake it for nothing. Bad sleep leads to bad mood! Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.c | 4 ++++ drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/intel_display.c | 2 +- 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index f197362..ad28a72 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -145,6 +145,10 @@ int i915_enable_pc8 __read_mostly = 0; module_param_named(enable_pc8, i915_enable_pc8, int, 0600); MODULE_PARM_DESC(enable_pc8, "Enable support for low power package C states (PC8+) (default: false)"); +int i915_pc8_timeout __read_mostly = 5000; +module_param_named(pc8_timeout, i915_pc8_timeout, int, 0600); +MODULE_PARM_DESC(pc8_timeout, "Number of msecs of idleness required to enter PC8+ (default: 5000)"); + bool i915_prefault_disable __read_mostly; module_param_named(prefault_disable, i915_prefault_disable, bool, 0600); MODULE_PARM_DESC(prefault_disable, diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 34c5af5..3138083 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1710,6 +1710,7 @@ extern int i915_disable_power_well __read_mostly; extern int i915_enable_ips __read_mostly; extern bool i915_fastboot __read_mostly; extern int i915_enable_pc8 __read_mostly; +extern int i915_pc8_timeout __read_mostly; extern bool i915_prefault_disable __read_mostly; extern int i915_suspend(struct drm_device *dev, pm_message_t state); diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 7d5b01a..ba3bdd5 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -6099,7 +6099,7 @@ static void __hsw_enable_package_c8(struct drm_i915_private *dev_priv) return; schedule_delayed_work(&dev_priv->pc8.enable_work, - msecs_to_jiffies(5 * 1000)); + msecs_to_jiffies(i915_pc8_timeout)); } static void __hsw_disable_package_c8(struct drm_i915_private *dev_priv) -- 1.8.1.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
