On Mon, Dec 26, 2016 at 12:25:19AM +0100, Rafael J. Wysocki wrote:

CC Mika and Andy.

Plus I don't think -stable is going to take your patches directly.

On Sun, Dec 25, 2016 at 11:21 AM, Hans de Goede [off-list ref] wrote:

quoted

The firmware on some cherrytrail devices wrongly adds _ADR 0 to their
entry describing the 80860F14 uid "2" sd-controller.

I believe the firmware writers intended this as a sdio function address,
but it is in the wrong place for this, so it gets interpreted as a pci
address, causing the node describing the sd-controller used for the
sdio-wifi to get seen as a firmware_node for the pci host bridge, rather
then being stand-alone device.

This commit adds a byt_sdio_setup function which detects this scenario
and removes the wrong firmware_node link from the pci host bridge, which
fixes acpi_create_platform_device returning NULL, leading to non-working
sdio-wifi.

BugLink: https://github.com/hadess/rtl8723bs/issues/80
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <redacted>
---
 drivers/acpi/acpi_lpss.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 373657f..df9cc66 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c

@@ -84,6 +84,7 @@ static const struct lpss_device_desc lpss_dma_desc = {
 };

 struct lpss_private_data {
+       struct acpi_device *adev;
        void __iomem *mmio_base;
        resource_size_t mmio_size;
        unsigned int fixed_clk_rate;

@@ -154,6 +155,33 @@ static void byt_i2c_setup(struct lpss_private_data *pdata)
        writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
 }

+static void byt_sdio_setup(struct lpss_private_data *pdata)
+{
+       unsigned long long adr;
+       acpi_status status;
+       struct device *dev;
+
+       /*
+        * Some firmware has a broken _ADR 0 enter for the 80860F14:2
+        * device, which causes it to get seen as the firmware_node
+        * for the pci host bridge, rather then a stand alone device.
+        *
+        * Check if this is the case, and if it is remove the link.
+        */
+       if (strcmp(acpi_device_uid(pdata->adev), "2") != 0)
+               return;
+
+       status = acpi_evaluate_integer(pdata->adev->handle, "_ADR", NULL, &adr);
+       if (ACPI_FAILURE(status) || adr != 0)
+               return;
+
+       dev = acpi_get_first_physical_node(pdata->adev);
+       if (!dev)
+               return;
+
+       acpi_unbind_one(dev);
+}

IIRC the _ADR 0 problem is not only limited to SDIO devices. I think we
should just fix the match heuristics in acpi_find_child_device() to
cover all other devices as well.

Something like below might do the job.

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 5ea5dc219f56..7cfd48f55b6f 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c

@@ -85,7 +85,7 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
 
 static int find_child_checks(struct acpi_device *adev, bool check_children)
 {
-	bool sta_present = true;
+	bool hid_present, sta_present = true;
 	unsigned long long sta;
 	acpi_status status;
 

@@ -98,7 +98,22 @@ static int find_child_checks(struct acpi_device *adev, bool check_children)
 	if (check_children && list_empty(&adev->children))
 		return -ENODEV;
 
-	return sta_present ? FIND_CHILD_MAX_SCORE : FIND_CHILD_MIN_SCORE;
+	/*
+	 * If there is a _HID or _CID present on a bus that is supposed to
+	 * be matched using _ADR, we prioritize those devices without ID
+	 * higher.
+	 *
+	 * This is because there are many BIOSes out there having ACPI
+	 * enumerated devices and the _ADR is set to 0. This will match the
+	 * root PCI bridge to the first found device with _ADR 0 which is
+	 * not always the right device.
+	 */
+	hid_present = !list_empty(&adev->pnp.ids);
+
+	if (sta_present)
+		return hid_present ? FIND_CHILD_MIN_SCORE : FIND_CHILD_MAX_SCORE;
+
+	return FIND_CHILD_MIN_SCORE;
 }
 
 struct acpi_device *acpi_find_child_device(struct acpi_device *parent,