[meta-freescale] [meta-fsl-arm/V2][PATCH 1/2] linux-imx_3.14.28: fix initial MMC device detection

Andreas Müller schnitzeltony at googlemail.com
Mon Jun 8 12:48:01 PDT 2015

On Mon, Jun 8, 2015 at 6:29 PM, Gary Thomas <gary at mlbassoc.com> wrote:
> On 2015-06-08 10:19, Eric Nelson wrote:
>> Hi Andreas,
>> On 06/08/2015 05:48 AM, Andreas Müller wrote:
>>> On Variscite Varsom we have three devices connected to MMC
>>> * MMC1: eMMC
>>> * MMC2: SDCard
>>> * MMC3: Wifi
>>> Without this patch only the first device was detected properly.
>>> I found two workarounds which can be removed by this patch:
>>> 1. Variscite: booting from SDCard made possible by renumbering MMC
>>> devices [1].
>>> 2. BoundaryDevices: Add workqueues for each mmc_host [2]. This had been
>>> tested
>>>     here too but causes crashing sdcard for huge storage traffic.
> Can you (Andreas) elaborate on this?  Is there a procedure to show this
> failure?
> I'd like to test it on my board(s) that have multiple [active] MMC devices.
As this patch fixes some race there are likely many configurations
around working properly and it it not easy to say which configuration
causes reproducibility.
Interesting note regarding race: Before I found this patch I tried to
gather more information and enabled CONFIG_MMC_DEBUG and all MMC
devices were properly detected! So thought 'OK not the best solution
but a workaround fixing my problem'. Fortunately my colleague
complained next morning for massive spam in kernel log so I had to
look for a proper solution...


More information about the meta-freescale mailing list