[Intel-gfx] [PATCH 3/6] drm/i915: Implement basic Displayport automated testing function for EDID operations
Jani Nikula
jani.nikula at linux.intel.com
Wed Jun 25 09:57:05 CEST 2014
On Wed, 25 Jun 2014, Todd Previte <tprevite at gmail.com> wrote:
> Implements some of the basic EDID tests for Displayport compliance. These tests
> include reading the EDID, verifying the checksum and writing the test responses
> back to the sink device.
>
> Signed-off-by: Todd Previte <tprevite at gmail.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 36 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 43fcabe..d060853 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3352,8 +3352,42 @@ 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 *edid_data = NULL;
> uint8_t test_result = DP_TEST_NAK;
> - return test_result;
> + uint32_t i = 0, ret = 0, checksum = 0;
> + struct drm_display_mode *use_mode = NULL;
> + dp_compliance_mode comp_mode_type = DP_COMPLIANCE_MODE_PREFERRED;
> + int mode_count = 0;
> +
> + edid_read = drm_get_edid(connector, adapter);
> +
> + DRM_DEBUG_KMS("Displayport: EDID automated test\n");
> +
> + if (edid_read) {
It is customary to have if (!edid_read) and bail out early. Then the
rest will be a happy day scenario with minimal indentation.
BR,
Jani.
> + test_result = true;
> + edid_data = (uint8_t*) edid_read;
> + // Compute checksum
> + for (i = 0; i < 128; i++)
> + checksum += edid_data[i];
> +
> + DRM_DEBUG_KMS("Displayport: EDID test - computed byte sum = %02x\n", checksum);
> + // Verify EDID checksum
> + if (checksum % 256 == 0) {
> + /* Write the checksum to EDID checksum register */
> + ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TEST_EDID_CHECKSUM, &edid_read->checksum, 1);
> + // Reponse is ACK and and checksum written
> + test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;
> + DRM_DEBUG_KMS("Displayport: EDID test - checksum = %02x\n", edid_read->checksum);
> + }
> + else {
> + // Invalid checksum, set for failsafe mode
> + comp_mode_type = DP_COMPLIANCE_MODE_FAILSAFE;
> + }
> + }
> + return test_result;
> }
>
> /* Displayport compliance testing - PHY pattern testing */
> --
> 1.9.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Jani Nikula, Intel Open Source Technology Center
More information about the Intel-gfx
mailing list