Re: implementing suspend to ram on cortex A8 based on linux 3.0.8

2012-03-13 Thread Barry Song
hi yang,

在 2012年3月10日 下午10:37,yang gqyang hustgqy...@gmail.com 写道:
  Thanks for your comment.
  Finally, i find out that i made a mistake.  The uart(8250) have not been
  restore after resume, instead, it use the configuration got from boot. The
  uart have not been restored correctly, so that ls can not output result
  correctly resulting in it seems that the busybox can not work correctly.
  Now, i still have a question about the uart: why the printk can work
  correctly, but the printf not?

  Before this, i believe that the printk work correctly, then the uart
  work ok. but now, i  need more reconsidaration about
  the relation between the printk, printf and uart.
  Can anyone give me some suggestion? Any comment is welcome, thanks a
  lot.

printk use struct console driver, it doesn't depend on a device node
for userspace.
printf actaully depends on uart_driver and a /dev/ttySx device node,
stdout and stderr are redirected to /dev/ttySx
uart is just a hardware which can be a tty or kernel console output.




-barry
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Re: implementing suspend to ram on cortex A8 based on linux 3.0.8

2012-03-10 Thread yang gqyang
 Thanks for your comment.
 Finally, i find out that i made a mistake.  The uart(8250) have not been
 restore after resume, instead, it use the configuration got from boot. The
 uart have not been restored correctly, so that ls can not output result
 correctly resulting in it seems that the busybox can not work correctly.
 Now, i still have a question about the uart: why the printk can work
 correctly, but the printf not?

 Before this, i believe that the printk work correctly, then the uart
 work ok. but now, i  need more reconsidaration about
 the relation between the printk, printf and uart.
 Can anyone give me some suggestion? Any comment is welcome, thanks a
 lot.


 在 2012年3月9日 下午10:08,Chenglie He chengjie...@linaro.org写道:

 Hi,

 I am doing this on A9, echo mem /sys/power/state is right, will trigger
 kernel to sleep.

 -jack


some recipient promote:
The message contains HTML subpart, therefore we consider it SPAM or
Outlook Virus
so i resend the email, hope it not disturb u. thanks a lot.
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Re: implementing suspend to ram on cortex A8 based on linux 3.0.8

2012-03-09 Thread Fabio Estevam
On Wed, Mar 7, 2012 at 12:05 PM, yang gqyang hustgqy...@gmail.com wrote:
 dear all:
 I am working on arm cortex a8 now, trying to implement suspend to ram
 based on linux 3.0.8.

Which CPU exactly are you using?
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