Re: [PATCH] MMC: Flush mmc workqueue late in the boot sequence

From: Pierre Ossman
Date: Thu May 10 2007 - 08:06:34 EST


Haavard Skinnemoen wrote:
> At some point before 2.6.20, the mmc subsystem moved the card
> detection code to its own workqueue. One consequence of this change
> is that when using an mmc card as a root device, the card may get
> detected after the init task attempts to mount the root filesystem,
> causing a kernel panic because the root device could not be opened.
>
> This patch adds a call to mmc_flush_scheduled_work() late in the boot
> sequence so that we can be sure the mmc card detection scans are
> complete before attempting to use an mmc device as a root device.
>
> Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>

NAK. This is still hackish and not a reliable, controlled way of handling the
issue of rootfs on removable media.

For reference, how is this handled in USB (which is conceptually identical)? The
normal case for removable media is usually an initrd that can wait for hotplug
events.

Rgds
Pierre

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