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>

drivers/gpu/drm/i915/i915_dma.c

@@ -35,6 +35,7 @@
 #include "i915_drv.h"
 #include "i915_trace.h"
 #include <linux/vgaarb.h>
+#include <linux/vga_switcheroo.h>
 
 /* Really want an OS-independent resettable timer.  Would like to have
  * this loop run for (eg) 3 sec, but have the timer reset every time
@@ -1199,6 +1200,32 @@ static unsigned int i915_vga_set_decode(void *cookie, bool state)
 		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
 }
 
+static void i915_switcheroo_set_state(struct pci_dev *pdev, enum vga_switcheroo_state state)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
+	if (state == VGA_SWITCHEROO_ON) {
+		printk(KERN_INFO "i915: switched off\n");
+		/* i915 resume handler doesn't set to D0 */
+		pci_set_power_state(dev->pdev, PCI_D0);
+		i915_resume(dev);
+	} else {
+		printk(KERN_ERR "i915: switched off\n");
+		i915_suspend(dev, pmm);
+	}
+}
+
+static bool i915_switcheroo_can_switch(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	bool can_switch;
+
+	spin_lock(&dev->count_lock);
+	can_switch = (dev->open_count == 0);
+	spin_unlock(&dev->count_lock);
+	return can_switch;
+}
+
 static int i915_load_modeset_init(struct drm_device *dev,
 				  unsigned long prealloc_start,
 				  unsigned long prealloc_size,
@@ -1260,6 +1287,12 @@ static int i915_load_modeset_init(struct drm_device *dev,
 	if (ret)
 		goto destroy_ringbuffer;
 
+	ret = vga_switcheroo_register_client(dev->pdev,
+					     i915_switcheroo_set_state,
+					     i915_switcheroo_can_switch);
+	if (ret)
+		goto destroy_ringbuffer;
+
 	intel_modeset_init(dev);
 
 	ret = drm_irq_install(dev);
@@ -1544,6 +1577,7 @@ int i915_driver_unload(struct drm_device *dev)
 			dev_priv->child_dev_num = 0;
 		}
 		drm_irq_uninstall(dev);
+		vga_switcheroo_unregister_client(dev->pdev);
 		vga_client_register(dev->pdev, NULL, NULL, NULL);
 	}
 
@@ -1611,6 +1645,7 @@ void i915_driver_lastclose(struct drm_device * dev)
 
 	if (!dev_priv || drm_core_check_feature(dev, DRIVER_MODESET)) {
 		drm_fb_helper_restore();
+		vga_switcheroo_process_delayed_switch();
 		return;
 	}
 

drivers/gpu/drm/i915/i915_drv.c

@@ -201,7 +201,7 @@ static int i915_drm_freeze(struct drm_device *dev)
 	return 0;
 }
 
-static int i915_suspend(struct drm_device *dev, pm_message_t state)
+int i915_suspend(struct drm_device *dev, pm_message_t state)
 {
 	int error;
 
@@ -255,7 +255,7 @@ static int i915_drm_thaw(struct drm_device *dev)
 	return error;
 }
 
-static int i915_resume(struct drm_device *dev)
+int i915_resume(struct drm_device *dev)
 {
 	if (pci_enable_device(dev->pdev))
 		return -EIO;

drivers/gpu/drm/i915/i915_drv.h

@@ -736,6 +736,8 @@ extern unsigned int i915_fbpercrtc;
 extern unsigned int i915_powersave;
 extern unsigned int i915_lvds_downclock;
 
+extern int i915_suspend(struct drm_device *dev, pm_message_t state);
+extern int i915_resume(struct drm_device *dev);
 extern void i915_save_display(struct drm_device *dev);
 extern void i915_restore_display(struct drm_device *dev);
 extern int i915_master_create(struct drm_device *dev, struct drm_master *master);

drivers/gpu/drm/i915/intel_fb.c

@@ -35,6 +35,7 @@
 #include <linux/delay.h>
 #include <linux/fb.h>
 #include <linux/init.h>
+#include <linux/vga_switcheroo.h>
 
 #include "drmP.h"
 #include "drm.h"
@@ -235,6 +236,7 @@ static int intelfb_create(struct drm_device *dev, uint32_t fb_width,
 			obj_priv->gtt_offset, fbo);
 
 	mutex_unlock(&dev->struct_mutex);
+	vga_switcheroo_client_fb_set(dev->pdev, info);
 	return 0;
 
 out_unpin:

drivers/gpu/drm/nouveau/nouveau_acpi.c

@@ -11,6 +11,8 @@
 #include "nouveau_drm.h"
 #include "nv50_display.h"
 
+#include <linux/vga_switcheroo.h>
+
 #define NOUVEAU_DSM_SUPPORTED 0x00
 #define NOUVEAU_DSM_SUPPORTED_FUNCTIONS 0x00
 
@@ -28,31 +30,30 @@
 #define NOUVEAU_DSM_POWER_SPEED 0x01
 #define NOUVEAU_DSM_POWER_STAMINA 0x02
 
-static int nouveau_dsm(struct drm_device *dev, int func, int arg, int *result)
-{
-	static char muid[] = {
-		0xA0, 0xA0, 0x95, 0x9D, 0x60, 0x00, 0x48, 0x4D,
-		0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4,
-	};
+static struct nouveau_dsm_priv {
+	bool dsm_detected;
+	acpi_handle dhandle;
+	acpi_handle dsm_handle;
+} nouveau_dsm_priv;
+
+static const char nouveau_dsm_muid[] = {
+	0xA0, 0xA0, 0x95, 0x9D, 0x60, 0x00, 0x48, 0x4D,
+	0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4,
+};
 
-	struct pci_dev *pdev = dev->pdev;
-	struct acpi_handle *handle;
+static int nouveau_dsm(acpi_handle handle, int func, int arg, int *result)
+{
 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
 	struct acpi_object_list input;
 	union acpi_object params[4];
 	union acpi_object *obj;
 	int err;
 
-	handle = DEVICE_ACPI_HANDLE(&pdev->dev);
-
-	if (!handle)
-		return -ENODEV;
-
 	input.count = 4;
 	input.pointer = params;
 	params[0].type = ACPI_TYPE_BUFFER;
-	params[0].buffer.length = sizeof(muid);
-	params[0].buffer.pointer = (char *)muid;
+	params[0].buffer.length = sizeof(nouveau_dsm_muid);
+	params[0].buffer.pointer = (char *)nouveau_dsm_muid;
 	params[1].type = ACPI_TYPE_INTEGER;
 	params[1].integer.value = 0x00000102;
 	params[2].type = ACPI_TYPE_INTEGER;
@@ -62,7 +63,7 @@ static int nouveau_dsm(struct drm_device *dev, int func, int arg, int *result)
 
 	err = acpi_evaluate_object(handle, "_DSM", &input, &output);
 	if (err) {
-		NV_INFO(dev, "failed to evaluate _DSM: %d\n", err);
+		printk(KERN_INFO "failed to evaluate _DSM: %d\n", err);
 		return err;
 	}
 
@@ -86,40 +87,119 @@ static int nouveau_dsm(struct drm_device *dev, int func, int arg, int *result)
 	return 0;
 }
 
-int nouveau_hybrid_setup(struct drm_device *dev)
+static int nouveau_dsm_switch_mux(acpi_handle handle, int mux_id)
 {
-	int result;
-
-	if (nouveau_dsm(dev, NOUVEAU_DSM_POWER, NOUVEAU_DSM_POWER_STATE,
-								&result))
-		return -ENODEV;
-
-	NV_INFO(dev, "_DSM hardware status gave 0x%x\n", result);
-
-	if (result) { /* Ensure that the external GPU is enabled */
-		nouveau_dsm(dev, NOUVEAU_DSM_LED, NOUVEAU_DSM_LED_SPEED, NULL);
-		nouveau_dsm(dev, NOUVEAU_DSM_POWER, NOUVEAU_DSM_POWER_SPEED,
-									NULL);
-	} else { /* Stamina mode - disable the external GPU */
-		nouveau_dsm(dev, NOUVEAU_DSM_LED, NOUVEAU_DSM_LED_STAMINA,
-									NULL);
-		nouveau_dsm(dev, NOUVEAU_DSM_POWER, NOUVEAU_DSM_POWER_STAMINA,
-									NULL);
-	}
+	return nouveau_dsm(handle, NOUVEAU_DSM_LED, mux_id, NULL);
+}
+
+static int nouveau_dsm_set_discrete_state(acpi_handle handle, enum vga_switcheroo_state state)
+{
+	int arg;
+	if (state == VGA_SWITCHEROO_ON)
+		arg = NOUVEAU_DSM_POWER_SPEED;
+	else
+		arg = NOUVEAU_DSM_POWER_STAMINA;
+	nouveau_dsm(handle, NOUVEAU_DSM_POWER, arg, NULL);
+	return 0;
+}
+
+static int nouveau_dsm_switchto(enum vga_switcheroo_client_id id)
+{
+	if (id == VGA_SWITCHEROO_IGD)
+		return nouveau_dsm_switch_mux(nouveau_dsm_priv.dsm_handle, NOUVEAU_DSM_LED_STAMINA);
+	else
+		return nouveau_dsm_switch_mux(nouveau_dsm_priv.dsm_handle, NOUVEAU_DSM_LED_SPEED);
+}
 
+static int nouveau_dsm_power_state(enum vga_switcheroo_client_id id,
+				   enum vga_switcheroo_state state)
+{
+	if (id == VGA_SWITCHEROO_IGD)
+		return 0;
+
+	return nouveau_dsm_set_discrete_state(nouveau_dsm_priv.dsm_handle, state);
+}
+
+static int nouveau_dsm_init(void)
+{
 	return 0;
 }
 
-bool nouveau_dsm_probe(struct drm_device *dev)
+static int nouveau_dsm_get_client_id(struct pci_dev *pdev)
 {
-	int support = 0;
+	if (nouveau_dsm_priv.dhandle == DEVICE_ACPI_HANDLE(&pdev->dev))
+		return VGA_SWITCHEROO_IGD;
+	else
+		return VGA_SWITCHEROO_DIS;
+}
+
+static struct vga_switcheroo_handler nouveau_dsm_handler = {
+	.switchto = nouveau_dsm_switchto,
+	.power_state = nouveau_dsm_power_state,
+	.init = nouveau_dsm_init,
+	.get_client_id = nouveau_dsm_get_client_id,
+};
 
-	if (nouveau_dsm(dev, NOUVEAU_DSM_SUPPORTED,
-				NOUVEAU_DSM_SUPPORTED_FUNCTIONS, &support))
+static bool nouveau_dsm_pci_probe(struct pci_dev *pdev)
+{
+	acpi_handle dhandle, nvidia_handle;
+	acpi_status status;
+	int ret;
+	uint32_t result;
+
+	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);
+	if (!dhandle)
+		return false;
+	status = acpi_get_handle(dhandle, "_DSM", &nvidia_handle);
+	if (ACPI_FAILURE(status)) {
 		return false;
+	}
 
-	if (!support)
+	ret= nouveau_dsm(nvidia_handle, NOUVEAU_DSM_SUPPORTED,
+			 NOUVEAU_DSM_SUPPORTED_FUNCTIONS, &result);
+	if (ret < 0)
 		return false;
 
+	nouveau_dsm_priv.dhandle = dhandle;
+	nouveau_dsm_priv.dsm_handle = nvidia_handle;
 	return true;
 }
+
+static bool nouveau_dsm_detect(void)
+{
+	char acpi_method_name[255] = { 0 };
+	struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
+	struct pci_dev *pdev = NULL;
+	int has_dsm = 0;
+	int vga_count = 0;
+	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
+		vga_count++;
+
+		has_dsm |= (nouveau_dsm_pci_probe(pdev) == true);
+	}
+
+	if (vga_count == 2 && has_dsm) {
+		acpi_get_name(nouveau_dsm_priv.dsm_handle, ACPI_FULL_PATHNAME, &buffer);
+		printk(KERN_INFO "VGA switcheroo: detected DSM switching method %s handle\n",
+		       acpi_method_name);
+		nouveau_dsm_priv.dsm_detected = true;
+		return true;
+	}
+	return false;
+}
+
+void nouveau_register_dsm_handler(void)
+{
+	bool r;
+
+	r = nouveau_dsm_detect();
+	if (!r)
+		return;
+
+	vga_switcheroo_register_handler(&nouveau_dsm_handler);
+}
+
+void nouveau_unregister_dsm_handler(void)
+{
+	vga_switcheroo_unregister_handler();
+}

drivers/gpu/drm/nouveau/nouveau_drv.c

@@ -135,7 +135,7 @@ nouveau_pci_remove(struct pci_dev *pdev)
 	drm_put_dev(dev);
 }
 
-static int
+int
 nouveau_pci_suspend(struct pci_dev *pdev, pm_message_t pm_state)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
@@ -233,7 +233,7 @@ nouveau_pci_suspend(struct pci_dev *pdev, pm_message_t pm_state)
 	return ret;
 }
 
-static int
+int
 nouveau_pci_resume(struct pci_dev *pdev)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
@@ -402,15 +402,18 @@ static int __init nouveau_init(void)
 			nouveau_modeset = 1;
 	}
 
-	if (nouveau_modeset == 1)
+	if (nouveau_modeset == 1) {
 		driver.driver_features |= DRIVER_MODESET;
+		nouveau_register_dsm_handler();
+	}
 
 	return drm_init(&driver);
 }
 
 static void __exit nouveau_exit(void)
 {
 	drm_exit(&driver);
+	nouveau_unregister_dsm_handler();
 }
 
 module_init(nouveau_init);

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -614,7 +614,6 @@ struct drm_nouveau_private {
 	} susres;
 
 	struct backlight_device *backlight;
-	bool acpi_dsm;
 
 	struct nouveau_channel *evo;
 
@@ -682,6 +681,9 @@ extern int nouveau_ignorelid;
 extern int nouveau_nofbaccel;
 extern int nouveau_noaccel;
 
+extern int nouveau_pci_suspend(struct pci_dev *pdev, pm_message_t pm_state);
+extern int nouveau_pci_resume(struct pci_dev *pdev);
+
 /* nouveau_state.c */
 extern void nouveau_preclose(struct drm_device *dev, struct drm_file *);
 extern int  nouveau_load(struct drm_device *, unsigned long flags);
@@ -848,19 +850,8 @@ extern int  nouveau_dma_init(struct nouveau_channel *);
 extern int  nouveau_dma_wait(struct nouveau_channel *, int size);
 
 /* nouveau_acpi.c */
-#ifdef CONFIG_ACPI
-extern int nouveau_hybrid_setup(struct drm_device *dev);
-extern bool nouveau_dsm_probe(struct drm_device *dev);
-#else
-static inline int nouveau_hybrid_setup(struct drm_device *dev)
-{
-	return 0;
-}
-static inline bool nouveau_dsm_probe(struct drm_device *dev)
-{
-	return false;
-}
-#endif
+void nouveau_register_dsm_handler(void);
+void nouveau_unregister_dsm_handler(void);
 
 /* nouveau_backlight.c */
 #ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT