Re: [PATCH v2 11/12] drm/i915/gen9: Add boot parameter for disabling DC6

Imre Deak
2015-11-11T19:04:27Z

On ma, 2015-11-09 at 16:48 +0100, Patrik Jakobsson wrote:
> v2: Use _unsafe (Jani)
>
> Signed-off-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/i915_params.c | 6 ++++++
> drivers/gpu/drm/i915/intel_runtime_pm.c | 4 ++--
> 3 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
> index c0252ef..5628c5a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2639,6 +2639,7 @@ struct i915_params {
> int panel_use_ssc;
> int vbt_sdvo_panel_type;
> int enable_rc6;
> + int enable_dc6;
> int enable_fbc;
> int enable_ppgtt;
> int enable_execlists;
> diff --git a/drivers/gpu/drm/i915/i915_params.c
> b/drivers/gpu/drm/i915/i915_params.c
> index 368df67..6457f3a 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -32,6 +32,7 @@ struct i915_params i915 __read_mostly = {
> .panel_use_ssc = -1,
> .vbt_sdvo_panel_type = -1,
> .enable_rc6 = -1,
> + .enable_dc6 = 1,
> .enable_fbc = -1,
> .enable_execlists = -1,
> .enable_hangcheck = true,
> @@ -79,6 +80,11 @@ MODULE_PARM_DESC(enable_rc6,
> "For example, 3 would enable rc6 and deep rc6, and 7 would
> enable everything. "
> "default: -1 (use per-chip default)");
>
> +module_param_named_unsafe(enable_dc6, i915.enable_dc6, int, 0400);
> +MODULE_PARM_DESC(enable_dc6,
> + "Enable power-saving display C-state 6. "
> + "(0 = disable; 1 = enable [default])");
> +

It would be more generic to have something like enable_dc, -1=per-chip
default, 0=disable, 1=up to dc5, 2=up to dc6.

> module_param_named_unsafe(enable_fbc, i915.enable_fbc, int, 0600);
> MODULE_PARM_DESC(enable_fbc,
> "Enable frame buffer compression for power savings "
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
> b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 95c3fcc..62c1273 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -708,7 +708,7 @@ static void gen9_dc_off_power_well_enable(struct
> drm_i915_private *dev_priv,
> static void gen9_dc_off_power_well_disable(struct drm_i915_private
> *dev_priv,
> struct i915_power_well
> *power_well)
> {
> - if (IS_SKYLAKE(dev_priv))
> + if (IS_SKYLAKE(dev_priv) && i915.enable_dc6)
> skl_enable_dc6(dev_priv);
> else
> gen9_enable_dc5(dev_priv);
> @@ -720,7 +720,7 @@ static void gen9_dc_off_power_well_sync_hw(struct
> drm_i915_private *dev_priv,
> if (power_well->count > 0) {
> gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> } else {
> - if (IS_SKYLAKE(dev_priv))
> + if (IS_SKYLAKE(dev_priv) && i915.enable_dc6)
> gen9_set_dc_state(dev_priv,
> DC_STATE_EN_UPTO_DC6);
> else
> gen9_set_dc_state(dev_priv,
> DC_STATE_EN_UPTO_DC5);