[Intel-gfx] [PATCH 5/9] drm/i915: Update the EDID automated compliance test function
Paulo Zanoni
przanoni at gmail.com
Wed Apr 8 10:02:12 PDT 2015
2015-03-31 14:15 GMT-03:00 Todd Previte <tprevite at gmail.com>:
> 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;
Variable "ret" is set but not used.
> +
> + edid_read = drm_get_edid(connector, adapter);
This is the additional edid read mentioned in the review of the previous patch.
> +
> + 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) */
Missing '*' char on the comment.
> + if (intel_dp->aux.i2c_nack_count > 0 ||
> + intel_dp->aux.i2c_defer_count > 0)
Since we're potentially reading edid more than once after the test
starts - as explained in the review of p4 -, do those nack/defer
counts make sense? Shouldn't we zero them before each edid read
attempt?
> + 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;
The compliance_test_data variable certainly needs a very good
documentation on what its bits means - possibly on top of its
definition, which is on patch 1 right now. Maybe it should be split
into more than one variable, since the bits that go inside it come
from different places. At least in the definition we should notice
"bits2-4 are from dp_helper.h". Another problem is that bits 0 and 1
from dp_helper.h can't be used there, which is even more confusing.
> + } 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;
I guess this chunk belongs to patch 6, especially since you rewrite
part of this new code there.
> }
> 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;
This is the chunk I was talking about in my review of p1.
> + unsigned long compliance_test_data;
> bool compliance_testing_active;
> bool compliance_edid_invalid;
> };
> --
> 1.9.1
>
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--
Paulo Zanoni
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