As pointed out by Wolfram Sang and already discussed at LKML [1] - an mmc host
driver may allow to unbind from its corresponding host device. If there is and
eMMC/SD card attached to the host, the mmc core will just try to cut the power
for it, without trying to make a graceful power-off, thus potentially we could
damage the card.

This series intends to fix this problem for eMMC/SD cards.

Please help to test and review!

Kind regards
Ulf Hansson

[1]
https://lore.kernel.org/all/20241007093447.33084-2-wsa+renesas@sang-engineering.com/

Ulf Hansson (5):
  mmc: core: Convert mmc_can_poweroff_notify() into a bool
  mmc: core: Further avoid re-storing power to the eMMC before a
    shutdown
  mmc: core: Convert into an enum for the poweroff-type for eMMC
  mmc: core: Add support for graceful host removal for eMMC
  mmc: core: Add support for graceful host removal for SD

 drivers/mmc/core/mmc.c | 66 +++++++++++++++++++++++++++++-------------
 drivers/mmc/core/sd.c  | 25 +++++++++-------
 2 files changed, 61 insertions(+), 30 deletions(-)

-- 
2.43.0

On Thu, Mar 20, 2025 at 03:00:31PM +0100, Ulf Hansson wrote:
> As pointed out by Wolfram Sang and already discussed at LKML [1] - an mmc host
> driver may allow to unbind from its corresponding host device. If there is and
> eMMC/SD card attached to the host, the mmc core will just try to cut the power
> for it, without trying to make a graceful power-off, thus potentially we could
> damage the card.
> 
> This series intends to fix this problem for eMMC/SD cards.
> 
> Please help to test and review!

Awesome! Thank you. Will surely check it out. Not before next week I am
afraid. But already looking forward to testing it!

> Awesome! Thank you. Will surely check it out. Not before next week I am
> afraid. But already looking forward to testing it!

So, I tested this with a Renesas Spider board (R-Car S4). The three
cases (shutdown, suspend, unbind) all lead to proper flagging if notify
can't be used or not. Only the question from patch 2 is left open.

But thank you, this has come a long way :)