Re: About mmc delayed workqueue.

[Chris Ball <cjb@laptop.org>]

Hi,

On Tue, Mar 29 2011, Ben Dooks wrote:
> On Wed, Mar 30, 2011 at 08:33:12AM +0900, NamJae Jeon wrote:
>> Hi. Chris.
>> 
>> I found some problem in mmc driver.  As you know, in nand trend, emmc
>> nand is used  booting device in embededd product.
>
> yeah, a really nasty trend if you ask me.
>  
>> It means that kernel, rootfs image is stored in emmc nand device. and
>> when rescaning mmc, mmc driver is working by delay work queue.
>> 
>> It can be cause "can not mount rootfs".  If  kernel mounting is faster
>> than mmc rescan, this problem would occur..
>> 
>> I changed to schedule_work instead of mmc_schedule_delayed_work. I can
>> make patch & test.
>> 
>> could you tell me your opinion ?
>
> Use root_wait on the commandline and it will wait for the root device
> to become reayd.

Ben's right that you should use "rootwait" (I don't think it works with
the underscore in the middle), rootdelay=5 if you want the boot to fail
if the partition isn't mounted after a little extra time, or an initrd
if you want full control over rootfs mounting.

These parameters are documented in Documentation/kernel-parameters.txt.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child