[PATCH] drm/amd/display: Add dm support for DP 1.4 Compliance edid corruption test

[Zuo, Jerry]

[AMD Official Use Only - Internal Distribution Only]

On 2020-04-29 1:58 p.m., Jerry (Fangzhi) Zuo wrote:
> It works together with drm framework
> "drm: Add support for DP 1.4 Compliance edid corruption test"
>
> Signed-off-by: Jerry (Fangzhi) Zuo <Jerry.Zuo at amd.com>
> ---
>  .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 40 ++++++-------------
>  1 file changed, 13 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> index c407f06cd1f5..b086d5c906e0 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> @@ -554,6 +554,7 @@ enum dc_edid_status dm_helpers_read_local_edid(
>                struct dc_sink *sink)
>  {
>        struct amdgpu_dm_connector *aconnector = link->priv;
> +     struct drm_connector *connector = &aconnector->base;
>        struct i2c_adapter *ddc;
>        int retry = 3;
>        enum dc_edid_status edid_status;
> @@ -571,6 +572,15 @@ enum dc_edid_status dm_helpers_read_local_edid(
>
>                edid = drm_get_edid(&aconnector->base, ddc);
>
> +             /* DP Compliance Test 4.2.2.6 */
> +             if (link->aux_mode && connector->edid_corrupt)
> +                     drm_dp_send_real_edid_checksum(&aconnector->dm_dp_aux.aux, connector->real_edid_checksum);
> +
> +             if (!edid && connector->edid_corrupt) {
> +                     connector->edid_corrupt = false;
> +                     return EDID_BAD_CHECKSUM;

You return EDID_BAD_CHECKSUM here but the surrounding loop uses
"edid_status == EDID_BAD_CHECKSUM" as condition to go again. Is this
duplicating functionality that dm_helpers_parse_edid_caps did?

Harry


It is not duplicate. You mentioned dm_helpers_parse_edid_caps() with retries is fallen into the 3rd checkup step below:
1. If base block is fetched with checksum mismatch, drm will set connector->edid_corrupt and return with Null edid buffer. This case will be handled as compliance test case 4.2.2.6, retuning EDID_BAD_CHECKSUM right away without going ahead to parse edid caps --> newly added
2. If edid buffer cannot be created, return EDID_NO_RESPONSE but do not set connector->edid_corrupt
3. For invalid extension blocks, drm doesn't set connector->edid_corrupt. This case will be further handled by dm_helpers_parse_edid_caps() with 3 times retries.
If failed any step above with EDID_BAD_CHECKSUM, will enable fail-safe mode in DC.

Jerry


> +             }
> +
>                if (!edid)
>                        return EDID_NO_RESPONSE;
>
> @@ -605,34 +615,10 @@ enum dc_edid_status dm_helpers_read_local_edid(
>                DRM_ERROR("EDID err: %d, on connector: %s",
>                                edid_status,
>                                aconnector->base.name);
> -     if (link->aux_mode) {
> -             union test_request test_request = { {0} };
> -             union test_response test_response = { {0} };
> -
> -             dm_helpers_dp_read_dpcd(ctx,
> -                                     link,
> -                                     DP_TEST_REQUEST,
> -                                     &test_request.raw,
> -                                     sizeof(union test_request));
> -
> -             if (!test_request.bits.EDID_READ)
> -                     return edid_status;
>
> -             test_response.bits.EDID_CHECKSUM_WRITE = 1;
> -
> -             dm_helpers_dp_write_dpcd(ctx,
> -                                     link,
> -                                     DP_TEST_EDID_CHECKSUM,
> -                                     &sink->dc_edid.raw_edid[sink->dc_edid.length-1],
> -                                     1);
> -
> -             dm_helpers_dp_write_dpcd(ctx,
> -                                     link,
> -                                     DP_TEST_RESPONSE,
> -                                     &test_response.raw,
> -                                     sizeof(test_response));
> -
> -     }
> +     /* DP Compliance Test 4.2.2.3 */
> +     if (link->aux_mode)
> +             drm_dp_send_real_edid_checksum(&aconnector->dm_dp_aux.aux, sink->dc_edid.raw_edid[sink->dc_edid.length-1]);
>
>        return edid_status;
>  }
>
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