[PATCH v2 0/3] Display switching support for Apple laptops

[PATCH v2 0/3] Display switching support for Apple laptops

[Seth Forshee]

This series adds display switching support for Apple laptops. The first
two patches contain preparatory changes to vga_switcheroo, and the third
contains the changes to support display switching with the gmux.

While these patches will allow switching the display mux, most Macbook
owners will not be able to switch GPUs in practice until the graphics
drivers are updated to deal with missing or incorrect vbios information
on Apple machines. These patches do fix an issue seen by some users of
Linux on Macbooks, however. These users will switch to the internal GPU
in OS X and then reboot into Linux to save power, but after S3 the gmux
gets reset to the discrete GPU. Adding the display mux support will fix
this problem by restoring the gmux state during resume.

v2: Disable interrupts during suspend and re-enable them during resume
    to fix timeouts waiting for switching to complete after S3

Thanks,
Seth


Andreas Heider (1):
  apple-gmux: Add display mux support

Seth Forshee (2):
  vga_switcheroo: Don't require handler init callback
  vga_switcheroo: Remove assumptions about registration/unregistration
    ordering

 drivers/gpu/drm/nouveau/nouveau_acpi.c |    6 -
 drivers/gpu/vga/vga_switcheroo.c       |   61 +++++----
 drivers/platform/x86/apple-gmux.c      |  224 ++++++++++++++++++++++++++++++++
 3 files changed, 262 insertions(+), 29 deletions(-)

[PATCH v2 1/3] vga_switcheroo: Don't require handler init callback

[Seth Forshee]

This callback is a no-op in nouveau, and the upcoming apple-gmux
switcheroo support won't require it either. Rather than forcing drivers
to stub it out, just make it optional and remove the callback from
nouveau.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 drivers/gpu/drm/nouveau/nouveau_acpi.c |    6 ------
 drivers/gpu/vga/vga_switcheroo.c       |    3 ++-
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index fc841e8..26ebffe 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -211,11 +211,6 @@ static int nouveau_dsm_power_state(enum vga_switcheroo_client_id id,
 	return nouveau_dsm_set_discrete_state(nouveau_dsm_priv.dhandle, state);
 }
 
-static int nouveau_dsm_init(void)
-{
-	return 0;
-}
-
 static int nouveau_dsm_get_client_id(struct pci_dev *pdev)
 {
 	/* easy option one - intel vendor ID means Integrated */
@@ -232,7 +227,6 @@ static int nouveau_dsm_get_client_id(struct pci_dev *pdev)
 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,
 };
 
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 5b3c7d1..ec9069d 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -98,7 +98,8 @@ static void vga_switcheroo_enable(void)
 	struct vga_switcheroo_client *client;
 
 	/* call the handler to init */
-	vgasr_priv.handler->init();
+	if (vgasr_priv.handler->init)
+		vgasr_priv.handler->init();
 
 	list_for_each_entry(client, &vgasr_priv.clients, list) {
 		if (client->id != -1)
-- 
1.7.9.5

[PATCH v2 2/3] vga_switcheroo: Remove assumptions about registration/unregistration ordering

[Seth Forshee]

vga_switcheroo assumes that the handler will be registered before the
last client, otherwise switching will not be enabled. Likewise it's
assumed that the handler will not be unregistered without at least one
client also being unregistered, otherwise switching will remain enabled
despite no longer having a handler. These assumptions cannot be enforced
if the handler is in a separate driver from both clients, as with the
gmux found in Apple laptops. Remove this assumption.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 drivers/gpu/vga/vga_switcheroo.c |   58 +++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index ec9069d..e25cf31 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -70,27 +70,12 @@ static struct vgasr_priv vgasr_priv = {
 	.clients = LIST_HEAD_INIT(vgasr_priv.clients),
 };
 
-int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
-{
-	mutex_lock(&vgasr_mutex);
-	if (vgasr_priv.handler) {
-		mutex_unlock(&vgasr_mutex);
-		return -EINVAL;
-	}
-
-	vgasr_priv.handler = handler;
-	mutex_unlock(&vgasr_mutex);
-	return 0;
-}
-EXPORT_SYMBOL(vga_switcheroo_register_handler);
-
-void vga_switcheroo_unregister_handler(void)
+static bool vga_switcheroo_ready(void)
 {
-	mutex_lock(&vgasr_mutex);
-	vgasr_priv.handler = NULL;
-	mutex_unlock(&vgasr_mutex);
+	/* we're ready if we get two clients + handler */
+	return !vgasr_priv.active &&
+	       vgasr_priv.registered_clients == 2 && vgasr_priv.handler;
 }
-EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
 
 static void vga_switcheroo_enable(void)
 {
@@ -114,6 +99,37 @@ static void vga_switcheroo_enable(void)
 	vgasr_priv.active = true;
 }
 
+int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
+{
+	mutex_lock(&vgasr_mutex);
+	if (vgasr_priv.handler) {
+		mutex_unlock(&vgasr_mutex);
+		return -EINVAL;
+	}
+
+	vgasr_priv.handler = handler;
+	if (vga_switcheroo_ready()) {
+		printk(KERN_INFO "vga_switcheroo: enabled\n");
+		vga_switcheroo_enable();
+	}
+	mutex_unlock(&vgasr_mutex);
+	return 0;
+}
+EXPORT_SYMBOL(vga_switcheroo_register_handler);
+
+void vga_switcheroo_unregister_handler(void)
+{
+	mutex_lock(&vgasr_mutex);
+	vgasr_priv.handler = NULL;
+	if (vgasr_priv.active) {
+		pr_info("vga_switcheroo: disabled\n");
+		vga_switcheroo_debugfs_fini(&vgasr_priv);
+		vgasr_priv.active = false;
+	}
+	mutex_unlock(&vgasr_mutex);
+}
+EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
+
 static int register_client(struct pci_dev *pdev,
 			   const struct vga_switcheroo_client_ops *ops,
 			   int id, bool active)
@@ -135,9 +151,7 @@ static int register_client(struct pci_dev *pdev,
 	if (client_is_vga(client))
 		vgasr_priv.registered_clients++;
 
-	/* if we get two clients + handler */
-	if (!vgasr_priv.active &&
-	    vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
+	if (vga_switcheroo_ready()) {
 		printk(KERN_INFO "vga_switcheroo: enabled\n");
 		vga_switcheroo_enable();
 	}
-- 
1.7.9.5

[PATCH v2 3/3] apple-gmux: Add display mux support

[Seth Forshee]

From: Andreas Heider <andreas@meetr.de>

Add support for the gmux display muxing functionality and register a mux
handler with vga_switcheroo.

Signed-off-by: Andreas Heider <andreas@meetr.de>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 drivers/platform/x86/apple-gmux.c |  224 +++++++++++++++++++++++++++++++++++++
 1 file changed, 224 insertions(+)

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 612b6f6..c72e81e 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -2,6 +2,7 @@
  *  Gmux driver for Apple laptops
  *
  *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
+ *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
@@ -19,6 +20,8 @@
 #include <linux/apple_bl.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/pci.h>
+#include <linux/vga_switcheroo.h>
 #include <acpi/video.h>
 #include <asm/io.h>
 
@@ -29,8 +32,17 @@ struct apple_gmux_data {
 	struct mutex index_lock;
 
 	struct backlight_device *bdev;
+
+	/* switcheroo data */
+	acpi_handle dhandle;
+	int gpe;
+	enum vga_switcheroo_client_id resume_client_id;
+	enum vga_switcheroo_state power_state;
+	struct completion powerchange_done;
 };
 
+static struct apple_gmux_data *apple_gmux_data;
+
 /*
  * gmux port offsets. Many of these are not yet used, but may be in the
  * future, and it's useful to have them documented here anyhow.
@@ -257,6 +269,146 @@ static const struct backlight_ops gmux_bl_ops = {
 	.update_status = gmux_update_status,
 };
 
+static int gmux_switchto(enum vga_switcheroo_client_id id)
+{
+	if (id == VGA_SWITCHEROO_IGD) {
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
+	} else {
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
+		gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
+	}
+
+	return 0;
+}
+
+static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
+				   enum vga_switcheroo_state state)
+{
+	INIT_COMPLETION(gmux_data->powerchange_done);
+
+	if (state == VGA_SWITCHEROO_ON) {
+		gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
+		gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
+		pr_debug("Discrete card powered up\n");
+	} else {
+		gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
+		gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
+		pr_debug("Discrete card powered down\n");
+	}
+
+	gmux_data->power_state = state;
+
+	if (gmux_data->gpe >= 0 &&
+	    !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
+						       msecs_to_jiffies(200)))
+		pr_warn("Timeout waiting for gmux switch to complete\n");
+
+	return 0;
+}
+
+static int gmux_set_power_state(enum vga_switcheroo_client_id id,
+				enum vga_switcheroo_state state)
+{
+	if (id == VGA_SWITCHEROO_IGD)
+		return 0;
+
+	return gmux_set_discrete_state(apple_gmux_data, state);
+}
+
+static int gmux_get_client_id(struct pci_dev *pdev)
+{
+	/*
+	 * Early Macbook Pros with switchable graphics use nvidia
+	 * integrated graphics. Hardcode that the 9400M is integrated.
+	 */
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL)
+		return VGA_SWITCHEROO_IGD;
+	else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
+		 pdev->device == 0x0863)
+		return VGA_SWITCHEROO_IGD;
+	else
+		return VGA_SWITCHEROO_DIS;
+}
+
+static enum vga_switcheroo_client_id
+gmux_active_client(struct apple_gmux_data *gmux_data)
+{
+	if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
+		return VGA_SWITCHEROO_IGD;
+
+	return VGA_SWITCHEROO_DIS;
+}
+
+static struct vga_switcheroo_handler gmux_handler = {
+	.switchto = gmux_switchto,
+	.power_state = gmux_set_power_state,
+	.get_client_id = gmux_get_client_id,
+};
+
+static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
+{
+	gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
+		    GMUX_INTERRUPT_DISABLE);
+}
+
+static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
+{
+	gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
+		    GMUX_INTERRUPT_ENABLE);
+}
+
+static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
+{
+	return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
+}
+
+static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
+{
+	u8 status;
+
+	/* to clear interrupts write back current status */
+	status = gmux_interrupt_get_status(gmux_data);
+	gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
+}
+
+static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
+{
+	u8 status;
+	struct pnp_dev *pnp = (struct pnp_dev *)context;
+	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+
+	status = gmux_interrupt_get_status(gmux_data);
+	gmux_disable_interrupts(gmux_data);
+	pr_debug("Notify handler called: status %d\n", status);
+
+	gmux_clear_interrupts(gmux_data);
+	gmux_enable_interrupts(gmux_data);
+
+	if (status & GMUX_INTERRUPT_STATUS_POWER)
+		complete(&gmux_data->powerchange_done);
+}
+
+static int gmux_suspend(struct pnp_dev *pnp, pm_message_t state)
+{
+	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+	gmux_data->resume_client_id = gmux_active_client(gmux_data);
+	gmux_disable_interrupts(gmux_data);
+	return 0;
+}
+
+static int gmux_resume(struct pnp_dev *pnp)
+{
+	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+	gmux_enable_interrupts(gmux_data);
+	gmux_switchto(gmux_data->resume_client_id);
+	if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
+		gmux_set_discrete_state(gmux_data, gmux_data->power_state);
+	return 0;
+}
+
 static int __devinit gmux_probe(struct pnp_dev *pnp,
 				const struct pnp_device_id *id)
 {
@@ -266,6 +418,11 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
 	struct backlight_device *bdev;
 	u8 ver_major, ver_minor, ver_release;
 	int ret = -ENXIO;
+	acpi_status status;
+	unsigned long long gpe;
+
+	if (apple_gmux_data)
+		return -EBUSY;
 
 	gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
 	if (!gmux_data)
@@ -353,8 +510,62 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
 #endif
 	apple_bl_unregister();
 
+	gmux_data->power_state = VGA_SWITCHEROO_ON;
+
+	gmux_data->dhandle = DEVICE_ACPI_HANDLE(&pnp->dev);
+	if (!gmux_data->dhandle) {
+		pr_err("Cannot find acpi handle for pnp device %s\n",
+		       dev_name(&pnp->dev));
+		ret = -ENODEV;
+		goto err_notify;
+	}
+
+	status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
+	if (ACPI_SUCCESS(status)) {
+		gmux_data->gpe = (int)gpe;
+
+		status = acpi_install_notify_handler(gmux_data->dhandle,
+						     ACPI_DEVICE_NOTIFY,
+						     &gmux_notify_handler, pnp);
+		if (ACPI_FAILURE(status)) {
+			pr_err("Install notify handler failed: %s\n",
+			       acpi_format_exception(status));
+			ret = -ENODEV;
+			goto err_notify;
+		}
+
+		status = acpi_enable_gpe(NULL, gmux_data->gpe);
+		if (ACPI_FAILURE(status)) {
+			pr_err("Cannot enable gpe: %s\n",
+			       acpi_format_exception(status));
+			goto err_enable_gpe;
+		}
+	} else {
+		pr_warn("No GPE found for gmux\n");
+		gmux_data->gpe = -1;
+	}
+
+	if (vga_switcheroo_register_handler(&gmux_handler)) {
+		ret = -ENODEV;
+		goto err_register_handler;
+	}
+
+	init_completion(&gmux_data->powerchange_done);
+	apple_gmux_data = gmux_data;
+	gmux_enable_interrupts(gmux_data);
+
 	return 0;
 
+err_register_handler:
+	if (gmux_data->gpe >= 0)
+		acpi_disable_gpe(NULL, gmux_data->gpe);
+err_enable_gpe:
+	if (gmux_data->gpe >= 0)
+		acpi_remove_notify_handler(gmux_data->dhandle,
+					   ACPI_DEVICE_NOTIFY,
+					   &gmux_notify_handler);
+err_notify:
+	backlight_device_unregister(bdev);
 err_release:
 	release_region(gmux_data->iostart, gmux_data->iolen);
 err_free:
@@ -366,8 +577,19 @@ static void __devexit gmux_remove(struct pnp_dev *pnp)
 {
 	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
 
+	vga_switcheroo_unregister_handler();
+	gmux_disable_interrupts(gmux_data);
+	if (gmux_data->gpe >= 0) {
+		acpi_disable_gpe(NULL, gmux_data->gpe);
+		acpi_remove_notify_handler(gmux_data->dhandle,
+					   ACPI_DEVICE_NOTIFY,
+					   &gmux_notify_handler);
+	}
+
 	backlight_device_unregister(gmux_data->bdev);
+
 	release_region(gmux_data->iostart, gmux_data->iolen);
+	apple_gmux_data = NULL;
 	kfree(gmux_data);
 
 	acpi_video_dmi_demote_vendor();
@@ -387,6 +609,8 @@ static struct pnp_driver gmux_pnp_driver = {
 	.probe		= gmux_probe,
 	.remove		= __devexit_p(gmux_remove),
 	.id_table	= gmux_device_ids,
+	.suspend	= gmux_suspend,
+	.resume		= gmux_resume
 };
 
 static int __init apple_gmux_init(void)
-- 
1.7.9.5