This is a note to let you know that I've just added the patch titled mmc: sdhci-pci: Try "cd" for card-detect lookup before using NULL to the 4.14-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-try-cd-for-card-detect-lookup-before-using-null.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From cdcefe6bd9df754f528ffc339d3cc143cea4ddf6 Mon Sep 17 00:00:00 2001 From: Rajat Jain <rajatja@xxxxxxxxxx> Date: Mon, 29 Oct 2018 15:17:01 -0700 Subject: mmc: sdhci-pci: Try "cd" for card-detect lookup before using NULL From: Rajat Jain <rajatja@xxxxxxxxxx> commit cdcefe6bd9df754f528ffc339d3cc143cea4ddf6 upstream. Problem: The card detect IRQ does not work with modern BIOS (that want to use _DSD to provide the card detect GPIO to the driver). Details: The mmc core provides the mmc_gpiod_request_cd() API to let host drivers request the gpio descriptor for the "card detect" pin. This pin is specified in the ACPI for the SDHC device: * Either as a resource using _CRS. This is a method used by legacy BIOS. (The driver needs to tell which resource index). * Or as a named property ("cd-gpios"/"cd-gpio") in _DSD (which internally points to an entry in _CRS). This way, the driver can lookup using a string. This is what modern BIOS prefer to use. This API finally results in a call to the following code: struct gpio_desc *acpi_find_gpio(..., const char *con_id,...) { ... /* Lookup gpio (using "<con_id>-gpio") in the _DSD */ ... if (!acpi_can_fallback_to_crs(adev, con_id)) return ERR_PTR(-ENOENT); ... /* Falling back to _CRS is allowed, Lookup gpio in the _CRS */ ... } Note that this means that if the ACPI has _DSD properties, the kernel will never use _CRS for the lookup (Because acpi_can_fallback_to_crs() will always be false for any device hat has _DSD entries). The SDHCI driver is thus currently broken on a modern BIOS, even if BIOS provides both _CRS (for index based lookup) and _DSD entries (for string based lookup). Ironically, none of these will be used for the lookup currently because: * Since the con_id is NULL, acpi_find_gpio() does not find a matching entry in DSDT. (The _DSDT entry has the property name = "cd-gpios") * Because ACPI contains DSDT entries, thus acpi_can_fallback_to_crs() returns false (because device properties have been populated from _DSD), thus the _CRS is never used for the lookup. Fix: Try "cd" for lookup in the _DSD before falling back to using NULL so as to try looking up in the _CRS. I've tested this patch successfully with both Legacy BIOS (that provide only _CRS method) as well as modern BIOS (that provide both _CRS and _DSD). Also the use of "cd" appears to be fairly consistent across other users of this API (other MMC host controller drivers). Link: https://lkml.org/lkml/2018/9/25/1113 Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> Fixes: f10e4bf6632b ("gpio: acpi: Even more tighten up ACPI GPIO lookups") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/mmc/host/sdhci-pci-core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/mmc/host/sdhci-pci-core.c +++ b/drivers/mmc/host/sdhci-pci-core.c @@ -1607,8 +1607,13 @@ static struct sdhci_pci_slot *sdhci_pci_ host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; if (slot->cd_idx >= 0) { - ret = mmc_gpiod_request_cd(host->mmc, NULL, slot->cd_idx, + ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx, slot->cd_override_level, 0, NULL); + if (ret && ret != -EPROBE_DEFER) + ret = mmc_gpiod_request_cd(host->mmc, NULL, + slot->cd_idx, + slot->cd_override_level, + 0, NULL); if (ret == -EPROBE_DEFER) goto remove; Patches currently in stable-queue which might be from rajatja@xxxxxxxxxx are queue-4.14/mmc-sdhci-pci-try-cd-for-card-detect-lookup-before-using-null.patch