From de8dcc3d2c0e08e5068ee1e26fc46415c15e3637 Mon Sep 17 00:00:00 2001
From: Daniel Drake <drake@endlessm.com>
Date: Tue, 12 Dec 2017 10:49:02 +0000
Subject: [PATCH] mmc: avoid removing non-removable hosts during suspend
Git-commit: de8dcc3d2c0e08e5068ee1e26fc46415c15e3637
Patch-mainline: v4.16-rc1
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/mmc/core/core.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2965,6 +2965,14 @@ static int mmc_pm_notify(struct notifier
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);