[3.13.y-ckt stable] Patch "mmc: sdhci-pxav3: fix unbalanced clock issues during probe" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mmc: sdhci-pxav3: fix unbalanced clock issues during probe

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d682ca99980bb587ecee71e4cd5af84d62a1db3a Mon Sep 17 00:00:00 2001
From: Jisheng Zhang <jszhang at marvell.com>
Date: Sun, 4 Jan 2015 23:15:47 +0800
Subject: mmc: sdhci-pxav3: fix unbalanced clock issues during probe

commit 62cf983ad84275f8580c807e5e596216c46773cf upstream.

Commit 0dcaa2499b7d ("sdhci-pxav3: Fix runtime PM initialization") tries
to fix one hang issue caused by calling sdhci_add_host() on a suspended
device. The fix enables the clock twice, once by clk_prepare_enable() and
another by pm_runtime_get_sync(), meaning that the clock will never be
gated at runtime PM suspend. I observed the power consumption regression on
Marvell BG2Q SoCs.

In fact, the fix is not correct. There still be a very small window
during which a runtime suspend might somehow occur after pm_runtime_enable()
but before pm_runtime_get_sync().

This patch fixes all of the two problems by just incrementing the usage
counter before pm_runtime_enable(). It also adjust the order of disabling
runtime pm and storing the usage count in the error path to handle clock
gating properly.

Signed-off-by: Jisheng Zhang <jszhang at marvell.com>
Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
[ kamal: backport to 3.13-stable: context ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mmc/host/sdhci-pxav3.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
index 793dacd..dc09e70 100644
--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -288,10 +288,11 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
 		}
 	}

-	pm_runtime_enable(&pdev->dev);
-	pm_runtime_get_sync(&pdev->dev);
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, PXAV3_RPM_DELAY_MS);
 	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
 	pm_suspend_ignore_children(&pdev->dev, 1);

 	ret = sdhci_add_host(host);
@@ -316,8 +317,8 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
 err_of_parse:
 err_cd_req:
 err_add_host:
-	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 	clk_disable_unprepare(clk);
 	clk_put(clk);
 err_clk_get:
--
1.9.1