vga_switcheroo: initial implementation (v15)

Many new laptops now come with 2 gpus, one to be used for low power
modes and one for gaming/on-ac applications. These GPUs are typically
wired to the laptop panel and VGA ports via a multiplexer unit which
is controlled via ACPI methods.

4 combinations of systems typically exist - with 2 ACPI methods.
Intel/ATI - Lenovo W500/T500 - use ATPX ACPI method
ATI/ATI - some ASUS - use ATPX ACPI Method
Intel/Nvidia - - use _DSM ACPI method
Nvidia/Nvidia -  - use _DSM ACPI method.

TODO:
This patch adds support for the ATPX method and initial bits
for the _DSM methods that need to written by someone with
access to the hardware.
Add a proper non-debugfs interface - need to get some proper
testing first.

v2: add power up/down support for both devices
on W500 puts i915/radeon into D3 and cuts power to radeon.

v3: redo probing methods, no DMI list, drm devices call to
register with switcheroo, it tries to find an ATPX method on
any device and once there is two devices + ATPX it inits the
switcher.

v4: ATPX msg handling using buffers - should work on more machines

v5: rearchitect after more mjg59 discussion - move ATPX handling to
    radeon driver.

v6: add file headers + initial nouveau bits (to be filled out).

v7: merge delayed switcher code.

v8: avoid suspend/resume of gpu that is off

v9: rearchitect - mjg59 is always right. - move all ATPX code to
radeon, should allow simpler DSM also proper ATRM handling

v10: add ATRM support for radeon BIOS, add mutex to lock vgasr_priv

v11: fix bug in resuming Intel for 2nd time.

v12: start fixing up nvidia code blindly.

v13: blindly guess at finishing nvidia code

v14: remove radeon audio hacks - fix up intel resume more like upstream

v15: clean up printks + remove unnecessary igd/dis pointers

mount debugfs

/sys/kernel/debug/vgaswitcheroo/switch - should exist if ATPX detected
 + 2 cards.

DIS - immediate change to discrete
IGD - immediate change to IGD
DDIS - delayed change to discrete
DIGD - delayed change to IGD
ON - turn on not in use
OFF - turn off not in use

Tested on W500 (Intel/ATI) and T500 (Intel/ATI)

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
new file mode 100644
index 000000000000..4b58ab1e8612
--- /dev/null
+++ b/include/linux/vga_switcheroo.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2010 Red Hat Inc.
+ * Author : Dave Airlie <airlied@redhat.com>
+ *
+ * Licensed under GPLv2
+ *
+ * vga_switcheroo.h - Support for laptop with dual GPU using one set of outputs
+ */
+
+#include <acpi/acpi.h>
+#include <linux/fb.h>
+
+enum vga_switcheroo_state {
+        VGA_SWITCHEROO_OFF,
+        VGA_SWITCHEROO_ON,
+};
+
+enum vga_switcheroo_client_id {
+        VGA_SWITCHEROO_IGD,
+        VGA_SWITCHEROO_DIS,
+        VGA_SWITCHEROO_MAX_CLIENTS,
+};
+
+struct vga_switcheroo_handler {
+        int (*switchto)(enum vga_switcheroo_client_id id);
+        int (*power_state)(enum vga_switcheroo_client_id id,
+                           enum vga_switcheroo_state state);
+        int (*init)(void);
+        int (*get_client_id)(struct pci_dev *pdev);
+};
+
+
+#if defined(CONFIG_VGA_SWITCHEROO)
+void vga_switcheroo_unregister_client(struct pci_dev *dev);
+int vga_switcheroo_register_client(struct pci_dev *dev,
+                                   void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state),
+                                   bool (*can_switch)(struct pci_dev *dev));
+
+void vga_switcheroo_client_fb_set(struct pci_dev *dev,
+                                  struct fb_info *info);
+
+int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler);
+void vga_switcheroo_unregister_handler(void);
+
+int vga_switcheroo_process_delayed_switch(void);
+
+#else
+
+static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
+static inline int vga_switcheroo_register_client(struct pci_dev *dev,
+                                          void (*set_gpu_state)(struct pci_dev *dev, enum vga_switcheroo_state),
+                                          bool (*can_switch)(struct pci_dev *dev)) { return 0; }
+static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
+static inline int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { return 0; }
+static inline void vga_switcheroo_unregister_handler(void) {}
+static inline int vga_switcheroo_process_delayed_switch(void) { return 0; }
+
+#endif