Return-Path: From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Daniel Drake , Ulf Hansson , Sasha Levin Subject: [PATCH AUTOSEL for 4.9 169/190] mmc: avoid removing non-removable hosts during suspend Date: Thu, 8 Mar 2018 05:00:07 +0000 Message-ID: <20180308045810.8041-169-alexander.levin@microsoft.com> References: <20180308045810.8041-1-alexander.levin@microsoft.com> In-Reply-To: <20180308045810.8041-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Daniel Drake [ 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 Signed-off-by: Ulf Hansson Signed-off-by: Sasha Levin --- drivers/mmc/core/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 2553d903a82b..cff5829790c9 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2974,6 +2974,14 @@ static int mmc_pm_notify(struct notifier_block *noti= fy_block, if (!err) break; =20 + 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); --=20 2.14.1