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>

5 files changed, 160 insertions, 62 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 48227e744753..0e0730a53137 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/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();
+}
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.c b/drivers/gpu/drm/nouveau/nouveau_drv.c
index da3b93b84502..f83ec65addba 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.c
+++ b/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 @@ out_abort:
         return ret;
 }
 
-static int
+int
 nouveau_pci_resume(struct pci_dev *pdev)
 {
         struct drm_device *dev = pci_get_drvdata(pdev);
@@ -402,8 +402,10 @@ 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);
 }
@@ -411,6 +413,7 @@ static int __init nouveau_init(void)
 static void __exit nouveau_exit(void)
 {
         drm_exit(&driver);
+        nouveau_unregister_dsm_handler();
 }
 
 module_init(nouveau_init);
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 1c15ef37b71c..85c05feab4f0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/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
diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index ea879a2efef3..1ebf22b664dd 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -36,6 +36,7 @@
 #include <linux/fb.h>
 #include <linux/init.h>
 #include <linux/screen_info.h>
+#include <linux/vga_switcheroo.h>
 
 #include "drmP.h"
 #include "drm.h"
@@ -370,6 +371,7 @@ nouveau_fbcon_create(struct drm_device *dev, uint32_t fb_width,
                                                 nvbo->bo.offset, nvbo);
 
         mutex_unlock(&dev->struct_mutex);
+        vga_switcheroo_client_fb_set(dev->pdev, info);
         return 0;
 
 out_unref:
diff --git a/drivers/gpu/drm/nouveau/nouveau_state.c b/drivers/gpu/drm/nouveau/nouveau_state.c
index a4851af5b05e..85d65b91389c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_state.c
+++ b/drivers/gpu/drm/nouveau/nouveau_state.c
@@ -29,6 +29,7 @@
 #include "drm_sarea.h"
 #include "drm_crtc_helper.h"
 #include <linux/vgaarb.h>
+#include <linux/vga_switcheroo.h>
 
 #include "nouveau_drv.h"
 #include "nouveau_drm.h"
@@ -371,6 +372,30 @@ out_err:
         return ret;
 }
 
+static void nouveau_switcheroo_set_state(struct pci_dev *pdev,
+                                         enum vga_switcheroo_state state)
+{
+        pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
+        if (state == VGA_SWITCHEROO_ON) {
+                printk(KERN_ERR "VGA switcheroo: switched nouveau on\n");
+                nouveau_pci_resume(pdev);
+        } else {
+                printk(KERN_ERR "VGA switcheroo: switched nouveau off\n");
+                nouveau_pci_suspend(pdev, pmm);
+        }
+}
+
+static bool nouveau_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;
+}
+
 int
 nouveau_card_init(struct drm_device *dev)
 {
@@ -384,6 +409,8 @@ nouveau_card_init(struct drm_device *dev)
                 return 0;
 
         vga_client_register(dev->pdev, dev, NULL, nouveau_vga_set_decode);
+        vga_switcheroo_register_client(dev->pdev, nouveau_switcheroo_set_state,
+                                       nouveau_switcheroo_can_switch);
 
         /* Initialise internal driver API hooks */
         ret = nouveau_init_engine_ptrs(dev);
@@ -617,11 +644,6 @@ int nouveau_load(struct drm_device *dev, unsigned long flags)
         NV_DEBUG(dev, "vendor: 0x%X device: 0x%X class: 0x%X\n",
                  dev->pci_vendor, dev->pci_device, dev->pdev->class);
 
-        dev_priv->acpi_dsm = nouveau_dsm_probe(dev);
-
-        if (dev_priv->acpi_dsm)
-                nouveau_hybrid_setup(dev);
-
         dev_priv->wq = create_workqueue("nouveau");
         if (!dev_priv->wq)
                 return -EINVAL;