Re: [PATCH RFC 00/12] Add Qualcomm SD Card Controller support.

From: Srinivas Kandagatla
Date: Tue May 20 2014 - 04:11:00 EST


Thanks Bjorn for testing this series.

On 19/05/14 23:08, Bjorn Andersson wrote:
On Mon, Apr 21, 2014 at 2:43 PM,<srinivas.kandagatla@xxxxxxxxxx> wrote:
>From: Srinivas Kandagatla<srinivas.kandagatla@xxxxxxxxxx>
[snip]
>
>This patches are tested in PIO mode on IFC8064 board with both eMMC and
>external SD card. I would appreciate any feedback/suggestions on the overall
>approach.
Hi Srini,

I finally got around to give this series a spin on our APQ8064 based
devices as well. I had a few reported CRC issues on our msm8960 based
devices, but thinks seems functionally "ok".

On APQ8064, the kernel finds the onboard eMMC and when mounting it I
get the following:

[ 1.624118] mmc0: new high speed MMC card at address 0001
[ 1.627521] mmcblk0: mmc0:0001 MAG2GA 14.5 GiB
[ 1.632714] mmcblk0boot0: mmc0:0001 MAG2GA partition 1 2.00 MiB
[ 1.636989] mmcblk0boot1: mmc0:0001 MAG2GA partition 2 2.00 MiB
[ 1.637393] Freeing unused kernel memory: 332K (c09c6000 - c0a19000)
[ 1.663379] mmcblk0: response CRC error sending r/w cmd command,

[ 2.292914] mmcblk0: response CRC error sending r/w cmd command,
card status 0xb00
[ 2.300985] mmcblk0: response CRC error sending r/w cmd command,


Any suggestions of what I could do to help you debug this?


There might be couple of reasons why this might happen,

First is the regluators. currently the upstream kernel does not have support for regulators. So, does the eMMC on your board work perfectly fine with the default 2.7v?

secondly it could be eMMC vendor specific quirks.

I stress tested eMMC on IFC6410 and I did not hit any issues as you mentioned.

Are you aware of any such quirks specific to the eMMC on your board?

thanks,
srini

Regards,
Bjorn
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