[Intel-gfx] [PATCH 2/2] drm/i915/psr: Remove wait_for_idle() for PSR2

[Dhinakaran Pandiyan]

CI runs show PSR2 does not go to IDLE with selective update enabled on
all PSR exit triggers. Specifically, logs indicate the hardware enters
"SLEEP Selective Update" and not "IDLE Reset state' like the kernel
expects. This check was added for PSR1 but incorrectly extended to PSR2,
remove this check for PSR2 as there is a plan to test only PSR1 on PSR2
panels.

Also add bspec reference to the comment about idle timeout.

Cc: Tarun Vyas <tarun.vyas at intel.com>
Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
 drivers/gpu/drm/i915/intel_psr.c | 39 ++++++++++++--------------------
 1 file changed, 14 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 5686ddaa6a72..09be9bfee2be 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -722,37 +722,26 @@ int intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state,
 {
 	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->base.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	i915_reg_t reg;
-	u32 mask;
-
-	if (!new_crtc_state->has_psr)
-		return 0;
 
 	/*
-	 * The sole user right now is intel_pipe_update_start(),
-	 * which won't race with psr_enable/disable, which is
-	 * where psr2_enabled is written to. So, we don't need
-	 * to acquire the psr.lock. More importantly, we want the
-	 * latency inside intel_pipe_update_start() to be as low
-	 * as possible, so no need to acquire psr.lock when it is
-	 * not needed and will induce latencies in the atomic
-	 * update path.
+	 * The sole user right now is intel_pipe_update_start(), which won't
+	 * race with psr_enable/disable where psr2_enabled is written to. So, we
+	 * don't need to acquire the psr.lock. More importantly, we want the
+	 * latency inside intel_pipe_update_start() to be as low as possible, so
+	 * no need to acquire psr.lock when it is not needed and will induce
+	 * latencies in the atomic update path.
 	 */
-	if (dev_priv->psr.psr2_enabled) {
-		reg = EDP_PSR2_STATUS;
-		mask = EDP_PSR2_STATUS_STATE_MASK;
-	} else {
-		reg = EDP_PSR_STATUS;
-		mask = EDP_PSR_STATUS_STATE_MASK;
-	}
+	if (!new_crtc_state->has_psr || READ_ONCE(dev_priv->psr.psr2_enabled))
+		return 0;
 
 	/*
-	 * Max time for PSR to idle = Inverse of the refresh rate +
-	 * 6 ms of exit training time + 1.5 ms of aux channel
-	 * handshake. 50 msec is defesive enough to cover everything.
+	 * From Bspec Panel Self Refresh (BDW+):
+	 * Max. time for PSR to idle = inverse of the refresh rate + 6 ms of
+	 * exit training time + 1.5 ms of aux channel handshake. 50 ms is
+	 * defensive enough to cover everything.
 	 */
-
-	return __intel_wait_for_register(dev_priv, reg, mask,
+	return __intel_wait_for_register(dev_priv, EDP_PSR_STATUS,
+					 EDP_PSR_STATUS_STATE_MASK,
 					 EDP_PSR_STATUS_STATE_IDLE, 2, 50,
 					 out_value);
 }
-- 
2.17.1