CODEWITHSUNDEEP
uefi
El-Coder-SB
El-Coder-SB

Reputation: 85

UEFI Shell: Access disabled device

Is there any way (by UEFI Shell commands or UEFI app) to access a device which was disabled in the "BIOS" menu?

Long Story:

When I enable the UART in the "BIOS" menu I get the following lines when calling devices:

78 R - -  -  1  1 Serial(0x1)
…
15A D - -  1  - - Serial(0x1)/Uart(115200,8,N,1)/UartFlowCtrl(Hardware)

The corresponding driver looks like this (output shortened)

 Handle B5 (D40B5D18) ...
 Driver Name    : <NONE>
 Image Name     : FvFile(54891A9E-763E-4377-8841-8D5C90D88CDE)
 Driver Type    : BUS
 Managing       :
   Ctrl[78] : Serial(0x1)
     Child[15A] : Serial(0x1)/Uart(115200,8,N,1)/UartFlowCtrl(Hardware)
   Ctrl[14E] : PciRoot(0x0)/Pci(0x1C,0x0)/Pci(0x0,0x0)
     Child[158] : PciRoot(0x0)/Pci(0x1C,0x0)/Pci(0x0,0x0)/Uart(115200,8,N,1)/UartFlowCtrl(Hardware)

If the UART is disabled I do not get the device entries and the driver drives only the PciRoot.

I thought I might get the device by reinitialize the driver. But as it has no name I have no idea how to do so.

Upvotes: 0

Views: 493

Answers (1)

prl
prl

Reputation: 12435

No, if the device is disabled in the BIOS settings, then it is literally turned off, so it’s not just a question of loading a driver for it. Hardware configurations set by the BIOS are locked after the BIOS writes to them, so they cannot be changed by software later without a reboot. You have to change the BIOS setting to enable the device.

Upvotes: 1

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