Re: [RFC v2 PATCH 2/4] block: add queue runtime pm callbacks

[Alan Stern]

On Thu, 24 May 2012, Lin Ming wrote:

> > When tested the patches, I found that kjournald and flusher thread
> > frequently resume the disk.
> 
> Just found that it's because "printk".
> 
> When disk is suspended, it prints out some message, for example,
> 
> [  670.597103] sd 0:0:0:0: [sda] Synchronizing SCSI cache
> [  670.597827] sd 0:0:0:0: [sda] Stopping disk
> 
> Then syslogd is waken up to write the log.
> So disk is resumed right after suspended.

:-)  Very amusing!  So if you change those two messages in sd_suspend
(and maybe also the message in sd_resume) from KERN_NOTICE to
KERN_DEBUG, things ought to improve.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/