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, 27 insertions, 5 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_state.c b/drivers/gpu/drm/nouveau/nouveau_state.c
index a4851af5b05..85d65b91389 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;