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apple-gmux: Add display mux support
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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>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
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Andreas Heider authored and Matthew Garrett committed Aug 17, 2012
1 parent f94f0f1 commit 76b487d
Showing 1 changed file with 224 additions and 0 deletions.
224 changes: 224 additions & 0 deletions drivers/platform/x86/apple-gmux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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>

Expand All @@ -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.
Expand Down Expand Up @@ -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)
{
Expand All @@ -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)
Expand Down Expand Up @@ -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:
Expand All @@ -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();
Expand All @@ -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)
Expand Down

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