v2: prefer seq_puts to seq_printf detected by Paulo Zanoni.
v3: PSR is disabled by default. Without userspace ready it
    will cause regression for kde and xdm users
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
                case PSR_NO_SINK:
                        seq_puts(m, "not supported by panel");
                        break;
+               case PSR_MODULE_PARAM:
+                       seq_puts(m, "disabled by flag");
+                       break;
                case PSR_CRTC_NOT_ACTIVE:
                        seq_puts(m, "crtc not active");
                        break;
 
 MODULE_PARM_DESC(i915_enable_ppgtt,
                "Enable PPGTT (default: true)");
 
+int i915_enable_psr __read_mostly = 0;
+module_param_named(enable_psr, i915_enable_psr, int, 0600);
+MODULE_PARM_DESC(enable_psr, "Enable PSR (default: false)");
+
 unsigned int i915_preliminary_hw_support __read_mostly = 0;
 module_param_named(preliminary_hw_support, i915_preliminary_hw_support, int, 0600);
 MODULE_PARM_DESC(preliminary_hw_support,
 
 enum no_psr_reason {
        PSR_NO_SOURCE, /* Not supported on platform */
        PSR_NO_SINK, /* Not supported by panel */
+       PSR_MODULE_PARAM,
        PSR_CRTC_NOT_ACTIVE,
        PSR_PWR_WELL_ENABLED,
        PSR_NOT_TILED,
 extern int i915_enable_fbc __read_mostly;
 extern bool i915_enable_hangcheck __read_mostly;
 extern int i915_enable_ppgtt __read_mostly;
+extern int i915_enable_psr __read_mostly;
 extern unsigned int i915_preliminary_hw_support __read_mostly;
 extern int i915_disable_power_well __read_mostly;
 extern int i915_enable_ips __read_mostly;
 
                return false;
        }
 
+       if (!i915_enable_psr) {
+               DRM_DEBUG_KMS("PSR disable by flag\n");
+               dev_priv->no_psr_reason = PSR_MODULE_PARAM;
+               return false;
+       }
+
        if (!intel_crtc->active || !crtc->fb || !crtc->mode.clock) {
                DRM_DEBUG_KMS("crtc not active for PSR\n");
                dev_priv->no_psr_reason = PSR_CRTC_NOT_ACTIVE;