[RFC PATCH 2/7] vga_switcheroo: Add helper function to get the active client

[Seth Forshee]

Add vga_switcheroo_get_active_client() to allow drivers to get the
active video client. This will be used by drivers wishing to temporarily
mux only the DDC to the inactive client.

Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
---
 drivers/gpu/vga/vga_switcheroo.c |   14 ++++++++++++++
 include/linux/vga_switcheroo.h   |    2 ++
 2 files changed, 16 insertions(+)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index ea6bcc2..e53f67d 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -205,6 +205,20 @@ find_active_client(struct list_head *head)
 	return NULL;
 }
 
+struct pci_dev *vga_switcheroo_get_active_client(void)
+{
+	struct vga_switcheroo_client *client;
+	struct pci_dev *pdev = NULL;
+
+	mutex_lock(&vgasr_mutex);
+	client = find_active_client(&vgasr_priv.clients);
+	if (client)
+		pdev = client->pdev;
+	mutex_unlock(&vgasr_mutex);
+	return pdev;
+}
+EXPORT_SYMBOL(vga_switcheroo_get_active_client);
+
 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
 {
 	struct vga_switcheroo_client *client;
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index b0d0839..e361858 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -61,6 +61,7 @@ void vga_switcheroo_unregister_handler(void);
 
 int vga_switcheroo_process_delayed_switch(void);
 
+struct pci_dev *vga_switcheroo_get_active_client(void);
 int vga_switcheroo_get_client_state(struct pci_dev *dev);
 
 #else
@@ -76,6 +77,7 @@ static inline int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 	int id, bool active) { return 0; }
 static inline void vga_switcheroo_unregister_handler(void) {}
 static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
+static inline struct pci_dev *vga_switcheroo_get_active_client(void) { return NULL; }
 static inline int vga_switcheroo_get_client_state(struct pci_dev *dev) { return VGA_SWITCHEROO_ON; }
 
 
-- 
1.7.9.5