Add a new (static inline) apple_gmux_detect() helper to apple-gmux.h
which can be used for gmux detection instead of apple_gmux_present().
The latter is not really reliable since an ACPI device with a HID
of APP000B is present on some devices without a gmux at all, as well
as on devices with a newer (unsupported) MMIO based gmux model.
This causes apple_gmux_present() to return false-postives on
a number of different Apple laptop models.
This new helper uses the same probing as the actual apple-gmux
driver, so that it does not return false positives.
To avoid code duplication the gmux_probe() function of the actual
driver is also moved over to using the new apple_gmux_detect() helper.
Fixes: 21245df307cb ("ACPI: video: Add Apple GMUX brightness control detection")
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/platform/x86/apple-gmux.c | 70 +++++++------------------
include/linux/apple-gmux.h | 85 ++++++++++++++++++++++++++++++-
2 files changed, 101 insertions(+), 54 deletions(-)
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index a0af01f6a0fd..9333f82cfa8a 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -226,23 +226,6 @@ static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
gmux_pio_write32(gmux_data, port, val);
}
-static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
-{
- u16 val;
-
- outb(0xaa, gmux_data->iostart + 0xcc);
- outb(0x55, gmux_data->iostart + 0xcd);
- outb(0x00, gmux_data->iostart + 0xce);
-
- val = inb(gmux_data->iostart + 0xcc) |
- (inb(gmux_data->iostart + 0xcd) << 8);
-
- if (val == 0x55aa)
- return true;
-
- return false;
-}
-
/**
* DOC: Backlight control
*
@@ -582,60 +565,43 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
int ret = -ENXIO;
acpi_status status;
unsigned long long gpe;
+ bool indexed = false;
+ u32 version;
if (apple_gmux_data)
return -EBUSY;
+ if (!apple_gmux_detect(pnp, &indexed)) {
+ pr_info("gmux device not present\n");
+ return -ENODEV;
+ }
+
gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
if (!gmux_data)
return -ENOMEM;
pnp_set_drvdata(pnp, gmux_data);
res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
- if (!res) {
- pr_err("Failed to find gmux I/O resource\n");
- goto err_free;
- }
-
gmux_data->iostart = res->start;
gmux_data->iolen = resource_size(res);
- if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
- pr_err("gmux I/O region too small (%lu < %u)\n",
- gmux_data->iolen, GMUX_MIN_IO_LEN);
- goto err_free;
- }
-
if (!request_region(gmux_data->iostart, gmux_data->iolen,
"Apple gmux")) {
pr_err("gmux I/O already in use\n");
goto err_free;
}
- /*
- * Invalid version information may indicate either that the gmux
- * device isn't present or that it's a new one that uses indexed
- * io
- */
-
- ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
- ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
- ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
- if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
- if (gmux_is_indexed(gmux_data)) {
- u32 version;
- mutex_init(&gmux_data->index_lock);
- gmux_data->indexed = true;
- version = gmux_read32(gmux_data,
- GMUX_PORT_VERSION_MAJOR);
- ver_major = (version >> 24) & 0xff;
- ver_minor = (version >> 16) & 0xff;
- ver_release = (version >> 8) & 0xff;
- } else {
- pr_info("gmux device not present\n");
- ret = -ENODEV;
- goto err_release;
- }
+ if (indexed) {
+ mutex_init(&gmux_data->index_lock);
+ gmux_data->indexed = true;
+ version = gmux_read32(gmux_data, GMUX_PORT_VERSION_MAJOR);
+ ver_major = (version >> 24) & 0xff;
+ ver_minor = (version >> 16) & 0xff;
+ ver_release = (version >> 8) & 0xff;
+ } else {
+ ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
+ ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
+ ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
}
pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
ver_release, (gmux_data->indexed ? "indexed" : "classic"));
diff --git a/include/linux/apple-gmux.h b/include/linux/apple-gmux.h
index 80efaaf89e07..47c04e7e3672 100644
--- a/include/linux/apple-gmux.h
+++ b/include/linux/apple-gmux.h
@@ -8,6 +8,8 @@
#define LINUX_APPLE_GMUX_H
#include <linux/acpi.h>
+#include <linux/io.h>
+#include <linux/pnp.h>
#define GMUX_ACPI_HID "APP000B"
@@ -35,14 +37,88 @@
#define GMUX_MIN_IO_LEN (GMUX_PORT_BRIGHTNESS + 4)
#if IS_ENABLED(CONFIG_APPLE_GMUX)
+static inline bool apple_gmux_is_indexed(unsigned long iostart)
+{
+ u16 val;
+
+ outb(0xaa, iostart + 0xcc);
+ outb(0x55, iostart + 0xcd);
+ outb(0x00, iostart + 0xce);
+
+ val = inb(iostart + 0xcc) | (inb(iostart + 0xcd) << 8);
+ if (val == 0x55aa)
+ return true;
+
+ return false;
+}
/**
- * apple_gmux_present() - detect if gmux is built into the machine
+ * apple_gmux_detect() - detect if gmux is built into the machine
+ *
+ * @pnp_dev: Device to probe or NULL to use the first matching device
+ * @indexed_ret: Returns (by reference) if the gmux is indexed or not
+ *
+ * Detect if a supported gmux device is present by actually probing it.
+ * This avoids the false positives returned on some models by
+ * apple_gmux_present().
+ *
+ * Return: %true if a supported gmux ACPI device is detected and the kernel
+ * was configured with CONFIG_APPLE_GMUX, %false otherwise.
+ */
+static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool *indexed_ret)
+{
+ u8 ver_major, ver_minor, ver_release;
+ struct resource *res;
+ bool indexed = false;
+
+ if (!pnp_dev) {
+ struct acpi_device *adev;
+ struct device *dev;
+
+ adev = acpi_dev_get_first_match_dev(GMUX_ACPI_HID, NULL, -1);
+ if (!adev)
+ return false;
+
+ dev = acpi_get_first_physical_node(adev);
+ if (!dev)
+ return false;
+
+ pnp_dev = to_pnp_dev(dev);
+ }
+
+ res = pnp_get_resource(pnp_dev, IORESOURCE_IO, 0);
+ if (!res)
+ return false;
+
+ if (resource_size(res) < GMUX_MIN_IO_LEN)
+ return false;
+
+ /*
+ * Invalid version information may indicate either that the gmux
+ * device isn't present or that it's a new one that uses indexed io.
+ */
+ ver_major = inb(res->start + GMUX_PORT_VERSION_MAJOR);
+ ver_minor = inb(res->start + GMUX_PORT_VERSION_MINOR);
+ ver_release = inb(res->start + GMUX_PORT_VERSION_RELEASE);
+ if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
+ indexed = apple_gmux_is_indexed(res->start);
+ if (!indexed)
+ return false;
+ }
+
+ if (indexed_ret)
+ *indexed_ret = indexed;
+
+ return true;
+}
+
+/**
+ * apple_gmux_present() - check if gmux ACPI device is present
*
* Drivers may use this to activate quirks specific to dual GPU MacBook Pros
* and Mac Pros, e.g. for deferred probing, runtime pm and backlight.
*
- * Return: %true if gmux is present and the kernel was configured
+ * Return: %true if gmux ACPI device is present and the kernel was configured
* with CONFIG_APPLE_GMUX, %false otherwise.
*/
static inline bool apple_gmux_present(void)
@@ -57,6 +133,11 @@ static inline bool apple_gmux_present(void)
return false;
}
+static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool *indexed_ret)
+{
+ return false;
+}
+
#endif /* !CONFIG_APPLE_GMUX */
#endif /* LINUX_APPLE_GMUX_H */
--
2.39.0
