mtd: pxa3xx_nand: issue with command time out

[Michael Wang]

On 01/19/2016 10:13 AM, Robert Jarzmik wrote:
>  From this analysis I think you have something broken in your platform, a driver
> taking a lock and blocking the scheduling or something like that. Your timeouts
> seem to come from there.
>
> If you want to add 2 prinks to validate the theory (and remove my debug logs
> which change the realtime behavior) :
>   - put one just before the "ret = IRQ_WAKE_THREAD";
>   - put the other on the first line of pxa3xx_nand_irq_thread()
>   - and calculate the difference.
Hi Robert,

Thank you very much for your help.

I have added the 2 printks, and I think you are right that there is 
something
blocking the scheduling.

[  146.372745] pxa3xx_nand_irq:700 IRQ_WAKE_THREAD status=2
[  146.378106] pxa3xx_nand_irq_thread:643
[  146.411117] pxa3xx_nand_irq:700 IRQ_WAKE_THREAD status=2
[  146.537124] pxa3xx_nand_irq_thread:643
       => irq thread was scheduled in 0.126 ms
[  146.541245] pxa3xx_nand_irq:700 IRQ_WAKE_THREAD status=2
[  146.546603] pxa3xx_nand_irq_thread:643

I will continue to investigate the cause of this delay.

Thanks,
Michael