Odroid-C1 regression with commit 4bc31edebde5 ("mmc: core: Set HS clock speed before sending HS CMD13")

[Martin Blumenstingl]

Hi Ulf,

On Wed, May 10, 2023 at 4:21 PM Ulf Hansson <ulf.hansson at linaro.org> wrote:
[...]
> Thanks for reporting - and my apologies for the long delay! It's been
> a busy period with lots of travelling for me.
Thank you for taking the time to look into this now - no need to apologize!

[...]
> > In this state I get:
> > # cat /sys/kernel/debug/mmc1/ios
> > clock:          52000000 Hz
> > actual clock:   51000000 Hz
> > vdd:            21 (3.3 ~ 3.4 V)
> > bus mode:       2 (push-pull)
> > chip select:    0 (don't care)
> > power mode:     2 (on)
> > bus width:      3 (8 bits)
> > timing spec:    9 (mmc HS200)
> > signal voltage: 1 (1.80 V)
> > driver type:    0 (driver type B)
>
> It looks to me that we are in the process of enabling the HS200 mode,
> but hangs at some point. Unless I am mistaken.
>
> More precisely, I suspect it's either the call to mmc_set_clock() or
> the call to mmc_switch_status(), in mmc_select_hs200(). Can you have a
> closer look to confirm this?
Indeed, removing mmc_set_clock() from mmc_select_hs200() also makes my
eMMC appear again on top of Linux 6.4-rc1.
See the attached diff in case it's not fully clear which
mmc_set_clock() call I removed.


Best regards,
Martin
-------------- next part --------------
A non-text attachment was scrubbed...
Name: drop-mmc_set_clock-from-mmc_select_hs200.diff
Type: text/x-patch
Size: 472 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-amlogic/attachments/20230510/8a83841c/attachment.bin>