linux-kernel - [PATCH 3.16.y-ckt 049/180] mmc: sdhci: Fix sdhci_runtime_pm_bus

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Date:	Wed,  3 Feb 2016 22:30:55 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Adrian Hunter <adrian.hunter@...el.com>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 049/180] mmc: sdhci: Fix sdhci_runtime_pm_bus_on/off()

3.16.7-ckt24 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Adrian Hunter <adrian.hunter@...el.com>

commit 5c671c410c8704800f4f1673b6f572137e7e6ddd upstream.

sdhci has a legacy facility to prevent runtime suspend if the
bus power is on.  This is needed in cases where the power to
the card is dependent on the bus power.  It is controlled by
a pair of functions: sdhci_runtime_pm_bus_on() and
sdhci_runtime_pm_bus_off().  These functions use a boolean
variable 'bus_on' to ensure changes are always paired.
There is an additional check for 'runtime_suspended' which is
the problem.  In fact, its use is ill-conceived as the only
requirement for the logic is that 'on' and 'off' are paired,
which is actually broken by the check, for example if the bus
power is turned on during runtime resume.  So remove  the check.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 drivers/mmc/host/sdhci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d7a5749da895..e0a4be732da8 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2632,7 +2632,7 @@ static int sdhci_runtime_pm_put(struct sdhci_host *host)

 static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)
 {
-	if (host->runtime_suspended || host->bus_on)
+	if (host->bus_on)
 		return;
 	host->bus_on = true;
 	pm_runtime_get_noresume(host->mmc->parent);
@@ -2640,7 +2640,7 @@ static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)

 static void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
 {
-	if (host->runtime_suspended || !host->bus_on)
+	if (!host->bus_on)
 		return;
 	host->bus_on = false;
 	pm_runtime_put_noidle(host->mmc->parent);