Patch "mmc: sdhci-acpi: Fix card detect race for Intel BXT/APL" has been added to the 4.4-stable tree

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

mmc: sdhci-acpi: Fix card detect race for Intel BXT/APL

to the 4.4-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-acpi-fix-card-detect-race-for-intel-bxt-apl.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Adrian Hunter <[email protected]>
Date: Tue, 9 Feb 2016 16:12:38 +0200
Subject: mmc: sdhci-acpi: Fix card detect race for Intel BXT/APL

From: Adrian Hunter <[email protected]>

commit 6a645dd87a5a506779810d7d9935c25fc2ef4687 upstream.

Intel BXT/APL use a card detect GPIO however the host controller will not enable bus power unless it's card detect also reflects the presence of a card. Unfortunately those 2 things race which can result in commands not starting, after which the controller does nothing and there is a 10 second wait for the driver's 10-second timer to timeout.

That is fixed by having the driver look also at the present state register to determine if the card is present. Consequently, provide a 'get_cd' mmc host operation for BXT/APL that does that.

---
 drivers/mmc/host/sdhci-acpi.c |   30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

@@ -146,6 +146,33 @@ static const struct sdhci_acpi_chip sdhc
 	.ops = &sdhci_acpi_ops_int,
 };
 
+static int bxt_get_cd(struct mmc_host *mmc)
+{
+	int gpio_cd = mmc_gpio_get_cd(mmc);
+	struct sdhci_host *host = mmc_priv(mmc);
+	unsigned long flags;
+	int ret = 0;
+
+	if (!gpio_cd)
+		return 0;
+
+	pm_runtime_get_sync(mmc->parent);
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	if (host->flags & SDHCI_DEVICE_DEAD)
+		goto out;
+
+	ret = !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT);
+out:
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	pm_runtime_mark_last_busy(mmc->parent);
+	pm_runtime_put_autosuspend(mmc->parent);
+
+	return ret;
+}
+
 static int sdhci_acpi_emmc_probe_slot(struct platform_device *pdev,
 				      const char *hid, const char *uid)
 {

@@ -196,6 +223,9 @@ static int sdhci_acpi_sd_probe_slot(stru
 
 	/* Platform specific code during sd probe slot goes here */
 
+	if (hid && !strcmp(hid, "80865ACA"))
+		host->mmc_host_ops.get_cd = bxt_get_cd;
+
 	return 0;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/mmc-sdhci-acpi-fix-card-detect-race-for-intel-bxt-apl.patch queue-4.4/mmc-mmc-fix-incorrect-use-of-driver-strength-switching-hs200-and-hs400.patch queue-4.4/mmc-sdhci-allow-override-of-get_cd-called-from-sdhci_request.patch queue-4.4/mmc-sdhci-pci-do-not-default-to-33-ohm-driver-strength-for-intel-spt.patch queue-4.4/mmc-sdio-fix-invalid-vdd-in-voltage-switch-power-cycle.patch queue-4.4/mmc-sdhci-fix-sdhci_runtime_pm_bus_on-off.patch queue-4.4/mmc-sdhci-allow-override-of-mmc-host-operations.patch queue-4.4/mmc-sdhci-fix-dma-descriptor-with-zero-data-length.patch queue-4.4/mmc-sdhci-pci-fix-card-detect-race-for-intel-bxt-apl.patch