Serial Port / Interface 表项详情

更新时间：2025/06/26

在Gitcode上查看源码

修订记录

openUBMC版本号	修订日期	修订人	修订内容
25.06	2025/06/26	pengqiang-gs	初稿，新增

Serial Port Sharing	Access Mode	Characteristics
disabled	disabled	Same behavior for both Modem and Direct Connect Mode If system power is On, Mux always set to system. When power is off Mux setting is unspecified. Set Serial/Modem Mux command is rejected. (See response data for the Set Serial/Modem Mux command). Escape sequence / pattern triggered switching is not available. Alerting Unavailable. BMC Power-on Default = mux set to system when system power is On. When power is off, mux setting is unspecified. BIOS Action at POST start: none required BIOS Action at POST end: none required
disabled	any except ‘disabled’	Same behavior for both Modem and Direct Connect Mode Mux always set to BMC. Set Serial/Modem Mux command is rejected. (See response data for the Set Serial/Modem Mux command). Escape sequence / pattern triggered switching is not available. Alerting available. BMC Power-on Default = mux set to BMC. BIOS Action at POST start: none required. BIOS Action at POST end: Recommend hiding/disabling baseboard serial controller.
enabled	enabled	Same behavior for both Modem and Direct Connect Mode Mux always set to system (except during alerting). Escape sequence / pattern triggered switching is disabled. Set Serial/Modem Mux command available. Alerting available. BMC Power-on Default = mux set to system. BIOS Action at POST start: none required. BIOS Action at POST end: none required.
enabled	pre-boot	BMC pays attention to Modem Ring Time parameter until mux is forced to system using Set Serial/Modem Mux command. Afterwards, BMC will not automatically take over mux for IPMI messaging (will not answer the phone) until next power down or system reset (unless commanded). Escape sequence / pattern triggered switching is available. Set Serial/Modem Mux command available. Alerting available. BMC will terminate call and automatically take the mux in order to send an alert, unless an IPMI Messaging Session is already in progress on the channel in which case alert will be “deferred” until channel becomes available for dial-out. BMC Power-on Default = If system power is off, or if Modem Ring Time >00h and <3Fh the power-on default mux setting is unspecified until RI or DCD is detected (see below), otherwise set to BMC. For Modem Mode, the BMC automatically takes over the connection upon power down, after system resets, and on detecting Ring based on Modem Ring Time parameter, except if a session is active - in which case the BMC will keep the connection (until the mux is forced to system using the Set Serial/Modem Mux command). If Modem Ring Time parameter is >00h and <3Fh, If system power is on and the Ring Time countdown is running, the mux will be set to system to allow the system to answer the modem call. BMC will take over mux if Ring Time expires while Ring is being detected via the RI signal. If system power is on, the mux will be returned to system when loss of connection (loss of DCD) is detected, or if the BMC takes the mux but is unable to establish a connection. If Ring Time = 00h, BMC will take mux during power down and after system resets as necessary to be able to answer the call via the modem. BMC will also take the mux and connect with the modem when a Ring is detected via the RI signal. Mux will be claimed by the BMC whenever loss of DCD connection is detected. To the BMC, this is essentially the same ‘phone answer’ and power down/reset behavior as in ‘Always Available’ mode. For Direct Connect Mode the BMC automatically takes the connection upon power down, after system resets, and whenever loss of DCD is detected (if DCD-based switching is enabled) except if a session is active - in which case the BMC will keep the connection (until the mux is forced to system using the Set Serial/Modem Mux command). BIOS Action at POST start: Request mux to system if BIOS console redirection enabled. BIOS Action at POST end: Force to system. Keep baseboard serial controller enabled.
enabled	always available	Escape sequence / pattern triggered switching is available. Set Serial/Modem Mux command available. Alerting available. BMC will terminate call and automatically take the mux in order to send an alert, unless an IPMI Messaging Session is already in progress on the channel in which case alert will be “deferred” until channel becomes available for dial-out. BMC Power-on Default = Mux set to BMC. For Modem Mode, the BMC automatically takes over mux on power down, system resets, when loss of DCD is detected, and upon detecting initial activity of RI. The BMC also initializes the modem whenever DCD loss is detected. The BMC ignores the Modem Ring Time parameter. For Direct Connect Mode, the BMC automatically takes the mux upon power down, after system resets, and whenever DCD is absent (if DCD-based switching is enabled). BIOS Action at POST start: Request mux to system if BIOS console redirection enabled. BIOS Action at POST end: Force mux to BMC. Recommend BIOS hides/disables baseboard serial controller.
enabled	shared	Escape sequence / pattern triggered switching is available. Set Serial/Modem Mux command available. Alerting available. BMC will terminate call and take mux in order to send an alert, unless an IPMI Messaging Session is already in progress on the channel - in which case alert will be “deferred” until channel becomes available for dial-out. BMC Power-on Default = If system power is off, or if Modem Ring Time >00h and<3Fh the power-on default mux setting is unspecified until RI or DCD is detected(see below), otherwise set to BMC. For Modem Mode, the BMC controls mux upon power down, after system resets, and on detecting Ring based on Modem Ring Time parameter, except if a session is active - in which case the BMC will keep the connection: If Modem Ring Time parameter is >00h, <3Fh. If system power is on and the Ring Time countdown is running, the mux will be set to system to allow the system to answer the modem call. BMC will take over mux if Ring Time expires while Ring is being detected via the RI signal. If system power is on, the mux will be returned to system when loss of connection (loss of DCD) is detected, or if the BMC takes the mux but is unable to establish a connection. If Ring Time = 00h, BMC will take mux during power down and after system resets as necessary to be able to answer the call via the modem. BMC will also take the mux and connect with the modem when a Ring is detected via the RI signal. Mux will be claimed by the BMC whenever loss of DCD connection is detected. To the BMC, this is essentially the same ‘phone answer’ and power down/reset behavior as in ‘Always Available’ mode. For Direct Connect Mode, the BMC takes the mux upon power down and after system resets, except if a session is active - in which case the BMC will keep the connection. Once power is up, the BMC will leave the mux in the state last commanded by software or an escape sequence and will not automatically take the mux unless DCD loss is detected (if DCD-based switching is enabled), or an alert needs to be sent. BIOS Action at POST start: Request mux to system if BIOS console redirection enabled. BIOS Action at POST end: None. BIOS leaves mux setting alone. Note that the Boot Options contain flags that remote software can use to request BIOS to place the mux into a given setting at POST end.