[Intel-gfx] [PATCH 5/9] drm/i915: Update the EDID automated compliance test function

[Todd Previte]

Updates the EDID compliance test function to perform the EDID read as
required by the tests. This read needs to take place in the kernel for
reasons of speed and efficiency. The results of the EDID read operations
are handed off to userspace so that the userspace app can set the display
mode appropriately for the test response.

The compliance_test_active flag now appears at the end of the individual
test handling functions. This is so that the kernel-side operations can
be completed without the risk of interruption from the userspace app
that is polling on that flag.

V2:
- Addressed mailing list feedback
- Removed excess debug messages
- Removed extraneous comments
- Fixed formatting issues (line length > 80)
- Updated the debug message in compute_edid_checksum to output hex values
  instead of decimal
V3:
- Addressed more list feedback
- Added the test_active flag to the autotest function
- Removed test_active flag from handler
- Added failsafe check on the compliance test active flag
  at the end of the test handler
- Fixed checkpatch.pl issues
V4:
- Removed the checksum computation function and its use as it has been
  rendered superfluous by changes to the core DRM EDID functions
- Updated to use the raw header corruption detection mechanism
- Moved the declaration of the test_data variable here

Signed-off-by: Todd Previte <tprevite at gmail.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 53 ++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  3 ++-
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 57f8e43..16d35903 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -41,6 +41,16 @@
 
 #define DP_LINK_CHECK_TIMEOUT	(10 * 1000)
 
+/* Compliance test status bits  */
+#define INTEL_DP_EDID_SHIFT_MASK	0
+#define INTEL_DP_EDID_OK		(0 << INTEL_DP_EDID_SHIFT_MASK)
+#define INTEL_DP_EDID_CORRUPT		(1 << INTEL_DP_EDID_SHIFT_MASK)
+
+#define INTEL_DP_RESOLUTION_SHIFT_MASK	4
+#define INTEL_DP_RESOLUTION_PREFERRED	(1 << INTEL_DP_RESOLUTION_SHIFT_MASK)
+#define INTEL_DP_RESOLUTION_STANDARD	(2 << INTEL_DP_RESOLUTION_SHIFT_MASK)
+#define INTEL_DP_RESOLUTION_FAILSAFE	(3 << INTEL_DP_RESOLUTION_SHIFT_MASK)
+
 struct dp_link_dpll {
 	int link_bw;
 	struct dpll dpll;
@@ -3766,7 +3776,44 @@ static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
 
 static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
 {
+	struct drm_connector *connector = &intel_dp->attached_connector->base;
+	struct i2c_adapter *adapter = &intel_dp->aux.ddc;
+	struct edid *edid_read = NULL;
 	uint8_t test_result = DP_TEST_NAK;
+	uint32_t ret = 0;
+
+	edid_read = drm_get_edid(connector, adapter);
+
+	if (drm_raw_edid_header_corrupt() == 1) {
+		DRM_DEBUG_DRIVER("EDID Header corrupted\n");
+		intel_dp->compliance_edid_invalid = 1;
+	}
+
+	if (edid_read == NULL || intel_dp->compliance_edid_invalid ||
+	    intel_dp->aux.i2c_defer_count > 6) {
+		/* Check for NACKs/DEFERs, use failsafe if detected
+		   (DP CTS 1.2 Core Rev 1.1, 4.2.2.4, 4.2.2.5) */
+		if (intel_dp->aux.i2c_nack_count > 0 ||
+			intel_dp->aux.i2c_defer_count > 0)
+			DRM_DEBUG_KMS("EDID read had %d NACKs, %d DEFERs\n",
+				      intel_dp->aux.i2c_nack_count,
+				      intel_dp->aux.i2c_defer_count);
+		intel_dp->compliance_test_data = DP_TEST_LINK_EDID_READ |
+						 INTEL_DP_EDID_CORRUPT  |
+						 INTEL_DP_RESOLUTION_FAILSAFE;
+	} else {
+		ret = drm_dp_dpcd_write(&intel_dp->aux,
+					DP_TEST_EDID_CHECKSUM,
+					&edid_read->checksum, 1);
+		test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;
+		intel_dp->compliance_test_data = DP_TEST_LINK_EDID_READ |
+						 INTEL_DP_EDID_OK       |
+						 INTEL_DP_RESOLUTION_STANDARD;
+	}
+
+	/* Set test active flag here so userspace doesn't interrupt things */
+	intel_dp->compliance_testing_active = 1;
+
 	return test_result;
 }
 
@@ -4596,6 +4643,12 @@ mst_fail:
 		DRM_DEBUG_KMS("MST device may have disappeared %d vs %d\n", intel_dp->is_mst, intel_dp->mst_mgr.mst_state);
 		intel_dp->is_mst = false;
 		drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
+	} else {
+		/* SST mode - handle short/long pulses here */
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+		intel_dp_check_link_status(intel_dp);
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+		ret = IRQ_HANDLED;
 	}
 put_power:
 	intel_display_power_put(dev_priv, power_domain);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 42e4251..fb6134f 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -649,7 +649,8 @@ struct intel_dp {
 				     uint32_t aux_clock_divider);
 
 	/* Displayport compliance testing */
-	unsigned long compliance_test_type;
+	unsigned char compliance_test_type;
+	unsigned long compliance_test_data;
 	bool compliance_testing_active;
 	bool compliance_edid_invalid;
 };
-- 
1.9.1