4.4-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Drake drake@endlessm.com
[ Upstream commit de8dcc3d2c0e08e5068ee1e26fc46415c15e3637 ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mmc/core/core.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2791,6 +2791,14 @@ int mmc_pm_notify(struct notifier_block if (!err) break;
+ if (!mmc_card_is_removable(host)) { + dev_warn(mmc_dev(host), + "pre_suspend failed for non-removable host: " + "%d\n", err); + /* Avoid removing non-removable hosts */ + break; + } + /* Calling bus_ops->remove() with a claimed host can deadlock */ host->bus_ops->remove(host); mmc_claim_host(host);