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

[Yang, York]

Hi, Carlo

	I don't understand. We can see that 9faac7b95 is all about DDR50. It should not affect the behavior of SDR50.
	Since the commit is very simple, you may remove the change one by one by yourself. And see if any difference occurs.
	Besides, please check if the card->sw_caps.sd3_bus_mode changes with or without DDR50 tuning enabled.

-----Original Message-----
From: carlo.caione at gmail.com [mailto:carlo.caione at gmail.com] On Behalf Of Carlo Caione
Sent: 2015年12月14日 18:57
To: Yang, York <weijuny at qti.qualcomm.com>
Cc: Carlo Caione <carlo at caione.org>; Ulf Hansson <ulf.hansson at linaro.org>; Barry Song <21cnbao at gmail.com>; linux-mmc <linux-mmc at vger.kernel.org>; DL-SHA-WorkGroupLinux <workgroup.linux at csr.com>; linux-arm-kernel at lists.infradead.org; Song, Barry <baohuas at qti.qualcomm.com>
Subject: Re: [PATCH 1/2] mmc: core: enable CMD19 tuning for DDR50 mode

On Mon, Dec 14, 2015 at 10:24 AM, Yang, York <weijuny at qti.qualcomm.com> wrote:
> Hi, Carlo
>
>         I don't think so. You may check the 9faac7b95, there are two changes in sd.c and sdhc.c.
>         Surely the change in sdhc.c will not affect ASUS X205TA (bcm43341) since it is a SDIO device.
>         Actually the calling sequence is this: mmc_sd_init_uhs_card() calls sdhci_execute_tuning(). In 9faac7b95, I enabled tuning for DDR50 in these two functions.
>         If your function calling sequence is mmc_sdio_init_uhs_card()->sdhci_execute_tuning(), the tuning will not carried out, since you didn't enable tuning for DDR50 in mmc_sdio_init_uhs_card().
>         Unless you call sdhci_execute_tuning directly, the tuning command may go through be sent out.

Hi Yang,

On the unmodified master what I see is:

- mmc_sdio_init_uhs_card() is called
- card->sw_caps.sd3_bus_mode is 0x14
- card->sw_caps.sd3_bus_mode & SD_MODE_UHS_SDR50 is actually verified (even though the tuning for DDR50 is not enabled)
- mmc_execute_tuning() is actually called

--
Carlo Caione