Re: [PATCH] mmc: Test bus-width for old MMC devices (v2)

Chris Ball
2010-12-16T23:40:44Z

Hi Takashi,

On Wed, Dec 15, 2010 at 08:14:24AM +0100, Takashi Iwai wrote:
> From: Aries Lee <arieslee@jmicron.com>
>
> Some old MMC devices fail with the 4/8 bits the driver tries to use
> exclusively. This patch adds a test for the given bus setup and falls
> back to the lower bit mode (until 1-bit mode) when the test fails.
>
> [Major rework and refactoring by tiwai]
> [Quirk addition and many fixes by prakity]
>
> v1->v2:
> - Rebased to the code with DDR support, set DDR bit properly
> - Return always error when bus-switching fallback failed
> - Define MMC_BUS_TEST_{R|W} in linux/mmc/mmc.h
> - Add quirk MMC_CAP_BUS_WIDTH_TEST -- default not used for compatibility
> - Ignore errors on BUS_TEST_W -- improves chances test will work
>
> Signed-off-by: Aries Lee <arieslee@jmicron.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> Signed-off-by: Philip Rakity <prakity@marvell.com>
> Tested-by: Philip Rakity <prakity@marvell.com>

This looks good, but adds a warning:

drivers/mmc/core/mmc.c: In function ‘mmc_init_card’:
drivers/mmc/core/mmc.c:547: warning: ‘bus_width’ may be used uninitialized in this function

Thanks,

--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child