Re: [PATCH] [MMC] Use own work queue

From: pHilipp Zabel
Date: Sun Oct 15 2006 - 05:52:27 EST


On 10/13/06, Russell King <rmk+lkml@xxxxxxxxxxxxxxxx> wrote:
On Mon, Oct 09, 2006 at 11:04:59PM +0200, Pierre Ossman wrote:
> pHilipp Zabel wrote:
> >
> > This patch makes pxamci stop working for me on a HTC Magician (PXA272).
> > Switching from 2.6.18 to 2.6.19-rc1 I got a kernel panic:
> >
> > mmc0: clock 0Hz busmode 1 powermode 0 cs 0 Vdd 0 width 0
> > PXAMCI: clkrt = 0 cmdat = 0
> > VFS: Cannot open root device "mmcblk0p2" or unknown-block(0,0)
> > Please append a correct "root=" boot option
> > Kernel panic - not syncing: VFS: Unable to mount root fs on
> > unknown-block(0,0)
> >
> > After removing this patch from 2.6.19-rc1, everything is working again.
> > Are there any changes to pxamci.c needed to be compatible with it?
> >
>
> No, the drivers shouldn't be affected. As this is a root device, my
> guess would be that you have a race in your bootup that is causing problem.

The problem is likely that the boot is continuing in parallel with
detecting the card, because the card detection is running in its own
separate thread. Meanwhile, the init thread is trying to read from
the as-yet missing root device and erroring out.

Thanks, I can work around this by using the rootdelay kernel parameter.
So does that mean this is the expected behavior, or should I do anything
in the bootup sequence to make the init process wait for mmc detection?

regards
Philipp
-
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/