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, 120 insertions, 40 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();
+}