ARM Technical Support Knowledge Articles

Why is DS-5 unable to control my target when debugging the Linux kernel via JTAG?

Applies to: DS-5

Answer

Applies to DS-5 v5.5 or later.

SYMPTOM

DS-5 debugger may lose control of the target during Linux kernel debug with error messages as follows:

Target Message: Could not determine target state
interrupt
ERROR(TAD9-NAL52):
! Unable to stop device 3
! Cannot attain state requested.


CAUSE

The behaviour can be triggered by kernel power management operations. In some targets setting CONFIG_CPU_IDLE=y in the kernel configuration can cause the on chip debug logic to be powered down. This breaks the communication between the debugger and the target, resulting in the debugger losing control or being unable to connect.

RESOLUTION

Rebuild the kernel with CONFIG_CPU_IDLE=n, reload the new kernel image and restart the debug session.

Article last edited on: 2011-05-23 14:35:20

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