Interrupts get disabled on USB access on MPC8272

Interrupts get disabled on USB access on MPC8272

[David Beamonte]

Hi,

I'm trying to make USB driver work on my MPC8272 with kernel 2.6.21.

The driver detects properly the root hub (the embedded controller), but 
when it tries to communicate with a device, the system seems to hang.

I have debugged the kernel and what I can see is that, once the 
processor tries to send a buffer of the USB controller, interrupts get 
disabled. And so, there is no ethernet, serial port, or whatever way of 
communication to the processor. With my debugger I can see that the 
kernel keeps running and executing cpu_idle() and so on. Furtheremore, 
jiffies increase, but no other interrupts occur.

Has anyone experienced a problem like this?

It seems to happen when buffers try to access external memory. Can it be 
related to bus arbitration?

Regards,

David

Re: Interrupts get disabled on USB access on MPC8272

[Scott Wood]

David Beamonte wrote:
> I have debugged the kernel and what I can see is that, once the 
> processor tries to send a buffer of the USB controller, interrupts get 
> disabled. And so, there is no ethernet, serial port, or whatever way of 
> communication to the processor. With my debugger I can see that the 
> kernel keeps running and executing cpu_idle() and so on. Furtheremore, 
> jiffies increase, but no other interrupts occur.

It's probably waiting for an interrupt that never came.

> It seems to happen when buffers try to access external memory. Can it be 
> related to bus arbitration?

Probably not; usually that sort of problem results in a hard lock-up.

-Scott