drm/i915: Enable fastboot by default on Skylake and newer

We really want to have fastboot enabled by default to avoid an ugly
modeset during boot.

Rather then enabling it everywhere, lets start with enabling it on
Skylake and newer.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190124130114.3967-1-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/i915_params.c

@@ -97,8 +97,10 @@ i915_param_named_unsafe(disable_power_well, int, 0400,
 
 i915_param_named_unsafe(enable_ips, int, 0600, "Enable IPS (default: true)");
 
-i915_param_named(fastboot, bool, 0600,
-	"Try to skip unnecessary mode sets at boot time (default: false)");
+i915_param_named(fastboot, int, 0600,
+	"Try to skip unnecessary mode sets at boot time "
+	"(0=disabled, 1=enabled) "
+	"Default: -1 (use per-chip default)");
 
 i915_param_named_unsafe(prefault_disable, bool, 0600,
 	"Disable page prefaulting for pread/pwrite/reloc (default:false). "

drivers/gpu/drm/i915/i915_params.h

@@ -63,10 +63,10 @@ struct drm_printer;
 	param(int, edp_vswing, 0) \
 	param(int, reset, 2) \
 	param(unsigned int, inject_load_failure, 0) \
+	param(int, fastboot, -1) \
 	/* leave bools at the end to not create holes */ \
 	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \
 	param(bool, enable_hangcheck, true) \
-	param(bool, fastboot, false) \
 	param(bool, prefault_disable, false) \
 	param(bool, load_detect_test, false) \
 	param(bool, force_reset_modeset_test, false) \

drivers/gpu/drm/i915/intel_display.c

@@ -11719,6 +11719,15 @@ pipe_config_err(bool adjust, const char *name, const char *format, ...)
 	va_end(args);
 }
 
+static bool fastboot_enabled(struct drm_i915_private *dev_priv)
+{
+	if (i915_modparams.fastboot != -1)
+		return i915_modparams.fastboot;
+
+	/* Enable fastboot by default on Skylake and newer */
+	return INTEL_GEN(dev_priv) >= 9;
+}
+
 static bool
 intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  struct intel_crtc_state *current_config,
@@ -11730,7 +11739,7 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 		(current_config->base.mode.private_flags & I915_MODE_FLAG_INHERITED) &&
 		!(pipe_config->base.mode.private_flags & I915_MODE_FLAG_INHERITED);
 
-	if (fixup_inherited && !i915_modparams.fastboot) {
+	if (fixup_inherited && !fastboot_enabled(dev_priv)) {
 		DRM_DEBUG_KMS("initial modeset and fastboot not set\n");
 		ret = false;
 	}