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

[Barry Song]

hi yang,

å 2012å3æ10æ äå10:37ïyang gqyang <hustgqyang@xxxxxxxxx> åéï
> ÂThanks for your comment.
> ÂFinally, i find out that i made a mistake. ÂThe uart(8250) have not been
> Ârestore after resume, instead, it use the configuration got from boot. The
> Âuart have not been restored correctly, so that "ls" can not output result
> Âcorrectly resulting in it seems that the busybox can not work correctly.
> ÂNow, i still have a question about the uart: why the "printk" can work
> Âcorrectly, but the "printf" not?
>
> ÂBefore this, i believe that the "printk" work correctly, then the uart
> Âwork ok. but now, i Âneed more reconsidaration about
> Âthe relation between the "printk", "printf" and "uart".
> ÂCan anyone give me some suggestion? Any comment is welcome, thanks a
> Âlot.

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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