Re: [PATCH] mmc: sh_mmcif: Support MMC_SLEEP_AWAKE command

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Simon,

On Wednesday 20 June 2012 15:42:38 Simon Horman wrote:
> On Wed, Jun 13, 2012 at 09:39:56AM +0200, Laurent Pinchart wrote:
> > On Wednesday 13 June 2012 10:12:01 Simon Horman wrote:
> > > On Tue, Jun 12, 2012 at 10:56:09PM +0200, Laurent Pinchart wrote:
> > > > The MMC_SLEEP_AWAKE and SD_IO_SEND_OP_COND commands share the same
> > > > opcode. SD_IO_SEND_OP_COND isn't supported by the SH MMCIF, but
> > > > MMC_SLEEP_AWAKE is. Discriminate between the two commands using the
> > > > command flags, and reject SD_IO_SEND_OP_COND only.
> > > > 
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > ---
> > > > 
> > > >  drivers/mmc/host/sh_mmcif.c |   14 ++++----------
> > > >  1 files changed, 4 insertions(+), 10 deletions(-)
> > > > 
> > > > Not supporting the MMC_SLEEP_AWAKE command makes system suspend fail
> > > > if an MMC or eMMC device supporting sleep/wake is connected. The issue
> > > > has been first noticed on the Armadillo 800 EVA board.
> > > 
> > > Hi Laurent,
> > > 
> > > Do you have a test-case for this?
> > 
> > echo mem > /sys/power/state on Armadillo 800 EVA was my test case. It
> > failed without the patch, and succeeds with it.
> 
> I'm not having much luck with or without your patch.
> 
> # echo mem > /sys/power/state
> echo: write error: No such device
> 
> I am using 3.5-rc3. With the armadillo default config + EXT3 + SUSPEND.
> Perhaps I am missing some options?

You're probably missing a patch. I'll send it as a reply to this e-mail.

> > > Also, did you check to make sure that the Mackerel still works?
> > 
> > Yes it still works. However, I have no way to test the MMC_SLEEP_AWAKE
> > command on the Mackerel board, as my MMC card doesn't support it (on the
> > Armadillo the eMMC chip supports the MMC_SLEEP_AWAKE command).
> > 
> > BTW, I wonder whether the current implementation is really the best one.
> > If the hardware doesn't support SD/SDIO commands, instead of intercepting
> > commands and rejecting the ones used by SD/SDIO at probe time, wouldn't it
> > be better for host drivers to tell that they don't support SD and/or SDIO
> > using flags in the mmc_host structure ?
> 
> I don't have any strong thoughts on this but your approach
> does sound interesting.

-- 
Regards,

Laurent Pinchart