Patch "mmc: sdhci-pci: Do not disable interrupts in sdhci_intel_set_power" has been added to the 4.10-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    mmc: sdhci-pci: Do not disable interrupts in sdhci_intel_set_power

to the 4.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mmc-sdhci-pci-do-not-disable-interrupts-in-sdhci_intel_set_power.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 027fb89e61054b4aedd962adb3e2003dec78a716 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@intel.com>
Date: Mon, 20 Mar 2017 19:50:30 +0200
Subject: mmc: sdhci-pci: Do not disable interrupts in sdhci_intel_set_power

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

commit 027fb89e61054b4aedd962adb3e2003dec78a716 upstream.

Disabling interrupts for even a millisecond can cause problems for some
devices. That can happen when Intel host controllers wait for the present
state to propagate.

The spin lock is not necessary here. Anything that is racing with changes
to the I/O state is already broken. The mmc core already provides
synchronization via "claiming" the host.

Although the spin lock probably should be removed from the code paths that
lead to this point, such a patch would touch too much code to be suitable
for stable trees. Consequently, for this patch, just drop the spin lock
while waiting.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mmc/host/sdhci-pci-core.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -452,6 +452,8 @@ static void sdhci_intel_set_power(struct
 	if (mode == MMC_POWER_OFF)
 		return;
 
+	spin_unlock_irq(&host->lock);
+
 	/*
 	 * Bus power might not enable after D3 -> D0 transition due to the
 	 * present state not yet having propagated. Retry for up to 2ms.
@@ -464,6 +466,8 @@ static void sdhci_intel_set_power(struct
 		reg |= SDHCI_POWER_ON;
 		sdhci_writeb(host, reg, SDHCI_POWER_CONTROL);
 	}
+
+	spin_lock_irq(&host->lock);
 }
 
 static const struct sdhci_ops sdhci_intel_byt_ops = {


Patches currently in stable-queue which might be from adrian.hunter@intel.com are

queue-4.10/mmc-sdhci-pci-do-not-disable-interrupts-in-sdhci_intel_set_power.patch
queue-4.10/mmc-sdhci-do-not-disable-interrupts-while-waiting-for-clock.patch