[AMD Official Use Only - Internal Distribution Only]
The error handling for edid read right now is categorized as:
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 the need to got ahead to parse edid caps.
2. If edid buffer cannot be created, return EDID_NO_RESPONSE but do not set connector->edid_corrupt
3. For extension blocks, drm returns any valid blocks. 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 all failed, will return EDID_BAD_CHECKSUM dc as well to enable fail-safe mode.
Regards,
Jerry
-----Original Message-----
From: Wentland, Harry <Harry.Wentland@xxxxxxx>
Sent: May 1, 2020 10:14 AM
To: Zuo, Jerry <Jerry.Zuo@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Wu, Hersen <hersenxs.wu@xxxxxxx>; S, Shirish <Shirish.S@xxxxxxx>
Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Siqueira, Rodrigo <Rodrigo.Siqueira@xxxxxxx>
Subject: Re: [PATCH] drm/amd/display: Add dm support for DP 1.4 Compliance edid corruption test
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@xxxxxxx>
> ---
> .../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
> +}
> +
> 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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