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drm/amd/display: Change AUX NACK behavior

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[Why]
Retrying on receiving a NACK can result in long overall EDID read times
in some cases.

[How]
Retry only on DEFER and return immediately on NACK.

Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: Ilya Bakoulin <Ilya.Bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Ilya Bakoulin 2022-08-04 13:44:51 -04:00 committed by Alex Deucher
parent 9f92c20279
commit 95bbbb88ed
1 changed files with 5 additions and 7 deletions
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12
drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
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@ -814,12 +814,6 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
"dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER");
retry_on_defer = true;
fallthrough;
case AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK:
if (*payload->reply == AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK)
DC_TRACE_LEVEL_MESSAGE(DAL_TRACE_LEVEL_INFORMATION,
LOG_FLAG_I2cAux_DceAux,
"dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK");
if (aux_defer_retries >= AUX_MIN_DEFER_RETRIES
&& defer_time_in_ms >= AUX_MAX_DEFER_TIMEOUT_MS) {
@ -848,7 +842,11 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
}
}
break;
case AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK:
DC_TRACE_LEVEL_MESSAGE(DAL_TRACE_LEVEL_INFORMATION,
LOG_FLAG_I2cAux_DceAux,
"dce_aux_transfer_with_retries: FAILURE: AUX_TRANSACTION_REPLY_I2C_OVER_AUX_NACK");
goto fail;
case AUX_TRANSACTION_REPLY_I2C_DEFER:
DC_TRACE_LEVEL_MESSAGE(DAL_TRACE_LEVEL_INFORMATION,
LOG_FLAG_I2cAux_DceAux,