Commit 95bbbb88 authored by Ilya Bakoulin's avatar Ilya Bakoulin Committed by Alex Deucher
Browse files

drm/amd/display: Change AUX NACK behavior 



[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: default avatarAric Cyr <Aric.Cyr@amd.com>
Acked-by: default avatarBrian Chang <Brian.Chang@amd.com>
Signed-off-by: default avatarIlya Bakoulin <Ilya.Bakoulin@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 9f92c202

drivers/gpu/drm/amd/display/dc/dce/dce_aux.c

+5 −7
Original line number Diff line number Diff line
@@ -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,