The Weibu F3C MiniPC has an onboard AP6255 module, presenting
two SDIO functions on a single MMC host (Bluetooth/btsdio and
WiFi/brcmfmac), and the mmc layer correctly detects this as
non-removable.
After suspend/resume, the wifi and bluetooth interfaces disappear
and do not get probed again.
The conditions here are:
1. During suspend, we reach mmc_pm_notify()
2. mmc_pm_notify() calls mmc_sdio_pre_suspend() to see if we can
suspend the SDIO host. However, mmc_sdio_pre_suspend() returns
-ENOSYS because btsdio_driver does not have a suspend method.
3. mmc_pm_notify() proceeds to remove the card
4. Upon resume, mmc_rescan() does nothing with this host, because of
the rescan_entered check which aims to only scan a non-removable
device a single time (i.e. during boot).
Fix the loss of functionality by detecting that we are unable to
suspend a non-removable host, so avoid the forced removal in that
case. The comment above this function already indicates that this
code was only intended for removable devices.
Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
de8dcc3d2c