[PATCH 1/2] mmc: core: enable CMD19 tuning for DDR50 mode

Carlo Caione carlo at caione.org
Mon Dec 14 01:13:55 PST 2015

On Mon, Dec 14, 2015 at 9:46 AM, Yang, York <weijuny at qti.qualcomm.com> wrote:
> Hi, Carlo
>         In 9faac7b95, tuning for DDR50 is enabled in mmc_sd_init_uhs_card(), so only SD card is affected.
>         This is based on the SD spec version 3.01.
>         mmc_sdio_init_uhs_card() is untouched. I don't know who add the code into mmc_sdio_init_uhs_card() and you may have a check on your side.

Hi Yang,
sorry for not being clear. Modifying mmc_sdio_init_uhs_card() was only
a test I did to check whether that could fix the issue, but it didn't.

Right now the situation is:
- In the latest master with commit 9faac7b95 WiFi is broken on the
ASUS X205TA (bcm43341)
- Reverting 9faac7b95 makes it working fine again

My conclusion is that issuing the CMD19 is basically breaking WiFi on
this platform.

Carlo Caione

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