drm/i915: Change i915.enable_psr parameter to use per platform default.

This will give us flexibility to enable PSR by default independently so
issues and corner cases in one platform won't affect others were we have
it working properly.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_params.c

@@ -38,7 +38,7 @@ struct i915_params i915 __read_mostly = {
 	.enable_execlists = -1,
 	.enable_hangcheck = true,
 	.enable_ppgtt = -1,
-	.enable_psr = 0,
+	.enable_psr = -1,
 	.preliminary_hw_support = IS_ENABLED(CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT),
 	.disable_power_well = -1,
 	.enable_ips = 1,
@@ -128,7 +128,8 @@ MODULE_PARM_DESC(enable_execlists,
 
 module_param_named_unsafe(enable_psr, i915.enable_psr, int, 0600);
 MODULE_PARM_DESC(enable_psr, "Enable PSR "
-		 "(0=disabled [default], 1=enabled - link mode chosen per-platform, 2=force link-standby mode, 3=force link-off mode)");
+		 "(0=disabled, 1=enabled - link mode chosen per-platform, 2=force link-standby mode, 3=force link-off mode) "
+		 "Default: -1 (use per-chip default)");
 
 module_param_named_unsafe(preliminary_hw_support, i915.preliminary_hw_support, int, 0600);
 MODULE_PARM_DESC(preliminary_hw_support,

drivers/gpu/drm/i915/intel_psr.c

@@ -778,6 +778,11 @@ void intel_psr_init(struct drm_device *dev)
 	dev_priv->psr_mmio_base = IS_HASWELL(dev_priv) ?
 		HSW_EDP_PSR_BASE : BDW_EDP_PSR_BASE;
 
+	/* Per platform default */
+	if (i915.enable_psr == -1) {
+		i915.enable_psr = 0;
+	}
+
 	/* Set link_standby x link_off defaults */
 	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
 		/* HSW and BDW require workarounds that we don't implement. */