nouveau: Support Optimus models for vga_switcheroo

Newer nVidia cards with Optimus do not support/use the DSM switching functions.
Instead, it require a DSM function to be called prior to bringing a device into
D3 state. No other _DSM calls are necessary before/after enabling/disabling a
device. Switching between discrete and integrated GPU is not supported by
this Optimus _DSM call, therefore return on the switching method.

Signed-off-by: Peter Lekensteyn <lekensteyn@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 42 insertions, 5 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 96756d0d6411..7814a760c164 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -30,6 +30,8 @@
 #define NOUVEAU_DSM_POWER_STAMINA 0x02
 
 #define NOUVEAU_DSM_OPTIMUS_FN 0x1A
+#define NOUVEAU_DSM_OPTIMUS_ARGS 0x03000001
+
 static struct nouveau_dsm_priv {
         bool dsm_detected;
         bool optimus_detected;
@@ -56,7 +58,8 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *
         struct acpi_object_list input;
         union acpi_object params[4];
         union acpi_object *obj;
-        int err;
+        int i, err;
+        char args_buff[4];
 
         input.count = 4;
         input.pointer = params;
@@ -68,7 +71,11 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *
         params[2].type = ACPI_TYPE_INTEGER;
         params[2].integer.value = func;
         params[3].type = ACPI_TYPE_BUFFER;
-        params[3].buffer.length = 0;
+        params[3].buffer.length = 4;
+        /* ACPI is little endian, AABBCCDD becomes {DD,CC,BB,AA} */
+        for (i = 0; i < 4; i++)
+                args_buff[i] = (arg >> i * 8) & 0xFF;
+        params[3].buffer.pointer = args_buff;
 
         err = acpi_evaluate_object(handle, "_DSM", &input, &output);
         if (err) {
@@ -180,6 +187,10 @@ static int nouveau_dsm_set_discrete_state(acpi_handle handle, enum vga_switchero
 
 static int nouveau_dsm_switchto(enum vga_switcheroo_client_id id)
 {
+        /* perhaps the _DSM functions are mutually exclusive, but prepare for
+         * the future */
+        if (!nouveau_dsm_priv.dsm_detected && nouveau_dsm_priv.optimus_detected)
+                return 0;
         if (id == VGA_SWITCHEROO_IGD)
                 return nouveau_dsm_switch_mux(nouveau_dsm_priv.dhandle, NOUVEAU_DSM_LED_STAMINA);
         else
@@ -192,6 +203,11 @@ static int nouveau_dsm_power_state(enum vga_switcheroo_client_id id,
         if (id == VGA_SWITCHEROO_IGD)
                 return 0;
 
+        /* Optimus laptops have the card already disabled in
+         * nouveau_switcheroo_set_state */
+        if (!nouveau_dsm_priv.dsm_detected && nouveau_dsm_priv.optimus_detected)
+                return 0;
+
         return nouveau_dsm_set_discrete_state(nouveau_dsm_priv.dhandle, state);
 }
 
@@ -278,15 +294,22 @@ static bool nouveau_dsm_detect(void)
         }
 
         if (vga_count == 2 && has_dsm && guid_valid) {
-                acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME, &buffer);
+                acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME,
+                        &buffer);
                 printk(KERN_INFO "VGA switcheroo: detected DSM switching method %s handle\n",
-                       acpi_method_name);
+                        acpi_method_name);
                 nouveau_dsm_priv.dsm_detected = true;
                 ret = true;
         }
 
-        if (has_optimus == 1)
+        if (has_optimus == 1) {
+                acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME,
+                        &buffer);
+                printk(KERN_INFO "VGA switcheroo: detected Optimus DSM method %s handle\n",
+                        acpi_method_name);
                 nouveau_dsm_priv.optimus_detected = true;
+                ret = true;
+        }
 
         return ret;
 }
@@ -302,6 +325,17 @@ void nouveau_register_dsm_handler(void)
         vga_switcheroo_register_handler(&nouveau_dsm_handler);
 }
 
+/* Must be called for Optimus models before the card can be turned off */
+void nouveau_switcheroo_optimus_dsm(void)
+{
+        u32 result = 0;
+        if (!nouveau_dsm_priv.optimus_detected)
+                return;
+
+        nouveau_optimus_dsm(nouveau_dsm_priv.dhandle, NOUVEAU_DSM_OPTIMUS_FN,
+                NOUVEAU_DSM_OPTIMUS_ARGS, &result);
+}
+
 void nouveau_unregister_dsm_handler(void)
 {
         vga_switcheroo_unregister_handler();
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 38134a9c7578..b82709828931 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -1055,12 +1055,14 @@ extern int  nouveau_dma_wait(struct nouveau_channel *, int slots, int size);
 #if defined(CONFIG_ACPI)
 void nouveau_register_dsm_handler(void);
 void nouveau_unregister_dsm_handler(void);
+void nouveau_switcheroo_optimus_dsm(void);
 int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len);
 bool nouveau_acpi_rom_supported(struct pci_dev *pdev);
 int nouveau_acpi_edid(struct drm_device *, struct drm_connector *);
 #else
 static inline void nouveau_register_dsm_handler(void) {}
 static inline void nouveau_unregister_dsm_handler(void) {}
+static inline void nouveau_switcheroo_optimus_dsm(void) {}
 static inline bool nouveau_acpi_rom_supported(struct pci_dev *pdev) { return false; }
 static inline int nouveau_acpi_get_bios_chunk(uint8_t *bios, int offset, int len) { return -EINVAL; }
 static inline int nouveau_acpi_edid(struct drm_device *dev, struct drm_connector *connector) { return -EINVAL; }
diff --git a/drivers/gpu/drm/nouveau/nouveau_state.c b/drivers/gpu/drm/nouveau/nouveau_state.c
index f5e98910d17f..f80c5e0762ff 100644
--- a/drivers/gpu/drm/nouveau/nouveau_state.c
+++ b/drivers/gpu/drm/nouveau/nouveau_state.c
@@ -525,6 +525,7 @@ static void nouveau_switcheroo_set_state(struct pci_dev *pdev,
                 printk(KERN_ERR "VGA switcheroo: switched nouveau off\n");
                 dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
                 drm_kms_helper_poll_disable(dev);
+                nouveau_switcheroo_optimus_dsm();
                 nouveau_pci_suspend(pdev, pmm);
                 dev->switch_power_state = DRM_SWITCH_POWER_OFF;
         }