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

Hi Simon,

On Wednesday 13 June 2012 10:12:01 Simon Horman wrote:

On Tue, Jun 12, 2012 at 10:56:09PM +0200, Laurent Pinchart wrote:

quoted

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.

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 ?

-- 
Regards,

Laurent Pinchart