drm/i915: Implement the intel_dp_autotest_edid function for DP EDID complaince tests

Updates the EDID compliance test function to perform the analyze and react to
the EDID data read as a result of a hot plug event. The results of this
analysis are handed off to userspace so that the userspace app can set the
display mode appropriately for the test result/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
V5:
- Update test active flag variable name to match the change in the
  first patch of the series.
- Relocated the test active flag declaration and initialization
  to this patch
V6:
- Updated to use the new flag for raw EDID header corruption
- Removed the extra EDID read from the autotest function
- Added the edid_checksum variable to struct intel_dp so that the
  autotest function can write it to the sink device
- Moved the update to the hpd_pulse function to another patch
- Removed extraneous constants
V7:
- Fixed erroneous placement of the checksum assignment. In some cases
  such as when the EDID read fails and is NULL, this causes a NULL ptr
  dereference in the kernel. Bad news. Fixed now.
V8:
- Updated to support the kfree() on the EDID data added previously
V9:
- Updated for the long_hpd flag propagation
V10:
- Updated to use actual checksum from the EDID read that occurs during
  normal hot plug path execution
- Removed variables from intel_dp struct that are no longer needed
- Updated the patch subject to more closely match the nature and contents
  of the patch
- Fixed formatting problem (long line)
V11:
- Removed extra debug messages
- Updated comments to be more informative
- Removed extra variable
V12:
- Removed the 4 bit offset of the resolution setting in compliance data
- Changed to DRM_DEBUG_KMS instead of DRM_DEBUG_DRIVER

Signed-off-by: Todd Previte <tprevite@gmail.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 91c8bf3..d0a8860 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -41,6 +41,12 @@
 
 #define DP_LINK_CHECK_TIMEOUT  (10 * 1000)
 
+/* Compliance test status bits  */
+#define INTEL_DP_RESOLUTION_SHIFT_MASK 0
+#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;
@@ -4079,6 +4085,39 @@ 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)
 {
        uint8_t test_result = DP_TEST_NAK;
+       struct intel_connector *intel_connector = intel_dp->attached_connector;
+       struct drm_connector *connector = &intel_connector->base;
+
+       if (intel_connector->detect_edid == NULL ||
+           connector->edid_corrupt == 1 ||
+           intel_dp->aux.i2c_defer_count > 6) {
+               /* Check EDID read for NACKs, DEFERs and corruption
+                * (DP CTS 1.2 Core r1.1)
+                *    4.2.2.4 : Failed EDID read, I2C_NAK
+                *    4.2.2.5 : Failed EDID read, I2C_DEFER
+                *    4.2.2.6 : EDID corruption detected
+                * Use failsafe mode for all cases
+                */
+               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 = INTEL_DP_RESOLUTION_FAILSAFE;
+       } else {
+               if (!drm_dp_dpcd_write(&intel_dp->aux,
+                                       DP_TEST_EDID_CHECKSUM,
+                                       &intel_connector->detect_edid->checksum,
+                                       1));
+                       DRM_DEBUG_KMS("Failed to write EDID checksum\n");
+
+               test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;
+               intel_dp->compliance_test_data = INTEL_DP_RESOLUTION_STANDARD;
+       }
+
+       /* Set test active flag here so userspace doesn't interrupt things */
+       intel_dp->compliance_test_active = 1;
+
        return test_result;
 }
 
@@ -4094,7 +4133,10 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
        uint8_t rxdata = 0;
        int status = 0;
 
+       intel_dp->compliance_test_active = 0;
        intel_dp->compliance_test_type = 0;
+       intel_dp->compliance_test_data = 0;
+
        intel_dp->aux.i2c_nack_count = 0;
        intel_dp->aux.i2c_defer_count = 0;
 

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index cf701ed..da553af 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -740,6 +740,8 @@ struct intel_dp {
 
        /* Displayport compliance testing */
        unsigned long compliance_test_type;
+       unsigned long compliance_test_data;
+       bool compliance_test_active;
 };
 
 struct intel_digital_port {