summaryrefslogtreecommitdiff
path: root/drivers/gpu/vga
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/gpu/vga')
-rw-r--r--drivers/gpu/vga/vga_switcheroo.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index cbd7c986d926..d349bf91dd11 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -30,6 +30,7 @@
#define pr_fmt(fmt) "vga_switcheroo: " fmt
+#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/debugfs.h>
#include <linux/fb.h>
@@ -308,7 +309,8 @@ static int register_client(struct pci_dev *pdev,
*
* Register vga client (GPU). Enable vga_switcheroo if another GPU and a
* handler have already registered. The power state of the client is assumed
- * to be ON.
+ * to be ON. Beforehand, vga_switcheroo_client_probe_defer() shall be called
+ * to ensure that all prerequisites are met.
*
* Return: 0 on success, -ENOMEM on memory allocation error.
*/
@@ -376,6 +378,31 @@ find_active_client(struct list_head *head)
}
/**
+ * vga_switcheroo_client_probe_defer() - whether to defer probing a given client
+ * @pdev: client pci device
+ *
+ * Determine whether any prerequisites are not fulfilled to probe a given
+ * client. Drivers shall invoke this early on in their ->probe callback
+ * and return %-EPROBE_DEFER if it evaluates to %true. Thou shalt not
+ * register the client ere thou hast called this.
+ *
+ * Return: %true if probing should be deferred, otherwise %false.
+ */
+bool vga_switcheroo_client_probe_defer(struct pci_dev *pdev)
+{
+ /*
+ * apple-gmux is needed on pre-retina MacBook Pro
+ * to probe the panel if pdev is the inactive GPU.
+ */
+ if (apple_gmux_present() && pdev != vga_default_device() &&
+ !vgasr_priv.handler_flags)
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(vga_switcheroo_client_probe_defer);
+
+/**
* vga_switcheroo_get_client_state() - obtain power state of a given client
* @pdev: client pci device
*