drm/i915/vlv: Update the DSI ULPS entry/exit sequence

We should keep DEVICE_READY bit set in the ULPS enter sequence. In
exit sequence also we should set DEVICE_READY, but thats causing
blankout for me. Also exit sequence is simplified as per hw team
recommendation.

This should fix -
[drm:intel_dsi_clear_device_ready] *ERROR* DSI LP not going Low

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80818
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 02f99d7..3fd0829 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -117,17 +117,18 @@ static void intel_dsi_device_ready(struct intel_encoder *encoder)
        /* bandgap reset is needed after everytime we do power gate */
        band_gap_reset(dev_priv);
 
+       I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+       usleep_range(2500, 3000);
+
        val = I915_READ(MIPI_PORT_CTRL(pipe));
        I915_WRITE(MIPI_PORT_CTRL(pipe), val | LP_OUTPUT_HOLD);
        usleep_range(1000, 1500);
-       I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_EXIT);
-       usleep_range(2000, 2500);
-       I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
-       usleep_range(2000, 2500);
-       I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
-       usleep_range(2000, 2500);
+
+       I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_EXIT);
+       usleep_range(2500, 3000);
+
        I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
-       usleep_range(2000, 2500);
+       usleep_range(2500, 3000);
 }
 
 static void intel_dsi_enable(struct intel_encoder *encoder)
@@ -271,23 +272,23 @@ static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
 
        DRM_DEBUG_KMS("\n");
 
-       I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+       I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_ENTER);
        usleep_range(2000, 2500);
 
-       I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_EXIT);
+       I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_EXIT);
        usleep_range(2000, 2500);
 
-       I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+       I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_ENTER);
        usleep_range(2000, 2500);
 
-       val = I915_READ(MIPI_PORT_CTRL(pipe));
-       I915_WRITE(MIPI_PORT_CTRL(pipe), val & ~LP_OUTPUT_HOLD);
-       usleep_range(1000, 1500);
-
        if (wait_for(((I915_READ(MIPI_PORT_CTRL(pipe)) & AFE_LATCHOUT)
                                        == 0x00000), 30))
                DRM_ERROR("DSI LP not going Low\n");
 
+       val = I915_READ(MIPI_PORT_CTRL(pipe));
+       I915_WRITE(MIPI_PORT_CTRL(pipe), val & ~LP_OUTPUT_HOLD);
+       usleep_range(1000, 1500);
+
        I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
        usleep_range(2000, 2500);