Problem with mmc DMA on panda board in 3.6

[Robert Nelson]

On Tue, Oct 2, 2012 at 5:24 PM, Tim Bird <tim.bird at am.sony.com> wrote:
> This is an early report - I'm just checking if anyone else has seen this.
>
> With Linux version v3.6, my PandaBoard (OMAP-based) no longer boots.  The
> system appears to fail to initialize the mmc controller.
>
> The kernel log message of interest appears to be this:
> [    1.690002] omap_hsmmc omap_hsmmc.0: unable to obtain RX DMA engine channel 6
>
> I can supply full kernel log messages and my .config if needed.
>
> I bisected the code and arrived at the following commit:
> -------
> commit 26b88520b80695a6fa5fd95b5d97c03f4daf87e0
> Author: Russell King <rmk+kernel at arm.linux.org.uk>
> Date:   Fri Apr 13 12:27:37 2012 +0100
>
>     mmc: omap_hsmmc: remove private DMA API implementation
>
>     Remove the private DMA API implementation from omap_hsmmc, making it
>     use entirely the DMA engine API.
>
>     Tested-by: Tony Lindgren <tony at atomide.com>
>     Tested-by: Venkatraman S <svenkatr at ti.com>
>     Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> -------
> The board works up until this commit.
> After this commit, the board hangs during boot after the message:
> [    1.852508] Waiting for root device /dev/mmcblk0p3...
> (and some other USB and network messages, which I presume
> are unrelated.)
>
> My questions are these:
> Has anyone else had problems with the PandaBoard (or other OMAP) on 3.6?
> Are there any related CONFIG_ variables I could change to try alternatives?
> What should I try next to debug this?

Check your config, to see if these are enabled:

CONFIG_DMADEVICES=y
CONFIG_DMA_OMAP=y

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/