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path: root/drivers/platform/x86/apple-gmux.c
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Diffstat (limited to 'drivers/platform/x86/apple-gmux.c')
-rw-r--r--drivers/platform/x86/apple-gmux.c48
1 files changed, 47 insertions, 1 deletions
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 66d6d22c239c..6808715003f6 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -22,6 +22,7 @@
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/vga_switcheroo.h>
+#include <linux/vgaarb.h>
#include <acpi/video.h>
#include <asm/io.h>
@@ -31,6 +32,7 @@ struct apple_gmux_data {
bool indexed;
struct mutex index_lock;
+ struct pci_dev *pdev;
struct backlight_device *bdev;
/* switcheroo data */
@@ -415,6 +417,23 @@ static int gmux_resume(struct device *dev)
return 0;
}
+static struct pci_dev *gmux_get_io_pdev(void)
+{
+ struct pci_dev *pdev = NULL;
+
+ while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
+ u16 cmd;
+
+ pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+ if (!(cmd & PCI_COMMAND_IO))
+ continue;
+
+ return pdev;
+ }
+
+ return NULL;
+}
+
static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
{
struct apple_gmux_data *gmux_data;
@@ -425,6 +444,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
int ret = -ENXIO;
acpi_status status;
unsigned long long gpe;
+ struct pci_dev *pdev = NULL;
if (apple_gmux_data)
return -EBUSY;
@@ -475,7 +495,7 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
ver_minor = (version >> 16) & 0xff;
ver_release = (version >> 8) & 0xff;
} else {
- pr_info("gmux device not present\n");
+ pr_info("gmux device not present or IO disabled\n");
ret = -ENODEV;
goto err_release;
}
@@ -483,6 +503,23 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
ver_release, (gmux_data->indexed ? "indexed" : "classic"));
+ /*
+ * Apple systems with gmux are EFI based and normally don't use
+ * VGA. In addition changing IO+MEM ownership between IGP and dGPU
+ * disables IO/MEM used for backlight control on some systems.
+ * Lock IO+MEM to GPU with active IO to prevent switch.
+ */
+ pdev = gmux_get_io_pdev();
+ if (pdev && vga_tryget(pdev,
+ VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
+ pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
+ pci_name(pdev));
+ ret = -EBUSY;
+ goto err_release;
+ } else if (pdev)
+ pr_info("locked IO for PCI:%s\n", pci_name(pdev));
+ gmux_data->pdev = pdev;
+
memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_PLATFORM;
props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
@@ -574,6 +611,10 @@ err_enable_gpe:
err_notify:
backlight_device_unregister(bdev);
err_release:
+ if (gmux_data->pdev)
+ vga_put(gmux_data->pdev,
+ VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+ pci_dev_put(pdev);
release_region(gmux_data->iostart, gmux_data->iolen);
err_free:
kfree(gmux_data);
@@ -593,6 +634,11 @@ static void gmux_remove(struct pnp_dev *pnp)
&gmux_notify_handler);
}
+ if (gmux_data->pdev) {
+ vga_put(gmux_data->pdev,
+ VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
+ pci_dev_put(gmux_data->pdev);
+ }
backlight_device_unregister(gmux_data->bdev);
release_region(gmux_data->iostart, gmux_data->iolen);