Re: [PATCH] ARM: dts: am57xx-idk: Remove support for voltage switching for SD card

[Tony Lindgren]

* Faiz Abbas <a0230074@xxxxxx> [190502 14:30]:
> Hi Tony,
> 
> On 02/05/19 7:50 PM, Tony Lindgren wrote:
> > * Faiz Abbas <faiz_abbas@xxxxxx> [190502 01:48]:
> >> If UHS speed modes are enabled, a compatible SD card switches down to
> >> 1.8V during enumeration. If after this a software reboot/crash takes
> >> place and on-chip ROM tries to enumerate the SD card, the difference in
> >> IO voltages (host @ 3.3V and card @ 1.8V) may end up damaging the card.
> >>
> >> The fix for this is to have support for power cycling the card in
> >> hardware (with a PORz/soft-reset line causing a power cycle of the
> >> card). Since am571x-, am572x- and am574x-idk don't have this
> >> capability, disable voltage switching for these boards.
> >>
> >> The major effect of this is that the maximum supported speed
> >> mode is now high speed(50 MHz) down from SDR104(200 MHz).
> > 
> > This sounds a bit urgent, does it also need a stable tag or is
> > it safe to apply against any earlier kernels?
> > 
> 
> This should be good to apply on any previous releases.

OK applying both your MMC patches into fixes today.

Thanks,

Tony