drm/i915/display: Allow PSR2 selective fetch to be enabled at run-time

Right now CI is blacklisting module reload, so we need to be able to
enable PSR2 selective fetch in run time to test this feature before
enable it by default.
Changes in IGT will also be needed.

v2:
- Fixed handling of I915_PSR_DEBUG_ENABLE_SEL_FETCH in
intel_psr_debug_set()

Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210209205036.351076-1-jose.souza@intel.com

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1430,6 +1430,7 @@ struct intel_psr {
 #define I915_PSR_DEBUG_DISABLE		0x01
 #define I915_PSR_DEBUG_ENABLE		0x02
 #define I915_PSR_DEBUG_FORCE_PSR1	0x03
+#define I915_PSR_DEBUG_ENABLE_SEL_FETCH	0x4
 #define I915_PSR_DEBUG_IRQ		0x10
 
 	u32 debug;

drivers/gpu/drm/i915/display/intel_psr.c

@@ -684,7 +684,8 @@ static bool intel_psr2_sel_fetch_config_valid(struct intel_dp *intel_dp,
 	struct intel_plane *plane;
 	int i;
 
-	if (!dev_priv->params.enable_psr2_sel_fetch) {
+	if (!dev_priv->params.enable_psr2_sel_fetch &&
+	    intel_dp->psr.debug != I915_PSR_DEBUG_ENABLE_SEL_FETCH) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "PSR2 sel fetch not enabled, disabled by parameter\n");
 		return false;
@@ -1448,7 +1449,8 @@ void intel_psr_update(struct intel_dp *intel_dp,
 	enable = crtc_state->has_psr;
 	psr2_enable = crtc_state->has_psr2;
 
-	if (enable == psr->enabled && psr2_enable == psr->psr2_enabled) {
+	if (enable == psr->enabled && psr2_enable == psr->psr2_enabled &&
+	    crtc_state->enable_psr2_sel_fetch == psr->psr2_sel_fetch_enabled) {
 		/* Force a PSR exit when enabling CRC to avoid CRC timeouts */
 		if (crtc_state->crc_enabled && psr->enabled)
 			psr_force_hw_tracking_exit(intel_dp);
@@ -1637,7 +1639,7 @@ int intel_psr_debug_set(struct intel_dp *intel_dp, u64 val)
 	int ret;
 
 	if (val & ~(I915_PSR_DEBUG_IRQ | I915_PSR_DEBUG_MODE_MASK) ||
-	    mode > I915_PSR_DEBUG_FORCE_PSR1) {
+	    mode > I915_PSR_DEBUG_ENABLE_SEL_FETCH) {
 		drm_dbg_kms(&dev_priv->drm, "Invalid debug mask %llx\n", val);
 		return -EINVAL;
 	}