Date:	Wed, 11 Jul 2012 02:25:31 +0200
From:	Andreas Heider <andreas@...tr.de>
To:	Matthew Garrett <mjg59@...f.ucam.org>,
	Arun Raghavan <arun.raghavan@...labora.co.uk>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] apple-gmux: Restore switch registers on suspend/resume

Thanks for adding me, seeing the gmux driver progress is always great.

Regarding the original patch: This is probably only useful when the gmux 
was switched in GRUB  and there's already a solution for the resume 
problem in userspace 
(http://ubuntuforums.org/showpost.php?p=10695119&postcount=261). Maybe 
the same could be achieved a bit cleaner by simply using a few parts of 
the switching patch?

Regarding the gmux switching patch: The patch itself should work and 
hopefully doesn't break stuff that wasn't broken before. But without 
additional fixes to i915/nouveau/etc. It won't be too useful either, 
although it should fix the resume issue.

I'll look into how well it works with the current kernel on the weekend, 
but I don't want to promise too much since time is still a bit of an 
issue for me.

Andreas

Am 10.07.12 18:35, schrieb Seth Forshee:
> [Adding Anreas on the Cc, looks like he was forgotten]
>
> On Tue, Jul 10, 2012 at 05:05:55PM +0100, Matthew Garrett wrote:
>> On Tue, Jul 10, 2012 at 09:09:53AM +0530, Arun Raghavan wrote:
>>> After suspend and resume, the values of these registers seem to change
>>> from what they were at suspend time, potentially preventing the actual
>>> output lines from being enabled post-resume. This saves relevant state
>>> at suspend and restores it when resumed.
>>>
>>> This is at least required on the MacBook Pro 8.2 when the Intel GPU is
>>> manually selected in GRUB config before the kernel is loaded.
>> I'd really rather add proper switcheroo support. Andreas, I have a patch
>> with your name on it that appears to work (attached) - any objections to
>> getting this merged?
> I agree completely. I've really been wanting to get the switcheroo
> support added, but I don't have hardware with working discrete graphics
> under EFI boot to work with.
>
> The patch seems to have some rough edges to work out, but once that's
> done I'd be in favor of merging it as long as it's working well.
>
> Seth
>
>> commit 225a5a4ba90e9cf3de836c936cd01e9828cd0765
>> Author: Matthew Garrett <mjg@...hat.com>
>> Date:   Thu Mar 22 09:28:27 2012 -0400
>>
>>      gmux switcheroo
>>
>> diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
>> index 694a15a..ef2c9ac 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@...onical.com>
>> + *  Copyright (C) 2010-2012 Andreas Heider <andreas@...tr.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
>> @@ -20,13 +21,22 @@
>>   #include <linux/slab.h>
>>   #include <acpi/video.h>
>>   #include <asm/io.h>
>> +#include <linux/pci.h>
>> +#include <linux/vga_switcheroo.h>
>> +#include <linux/delay.h>
>>   
>> -struct apple_gmux_data {
>> +static struct apple_gmux_data {
>>   	unsigned long iostart;
>>   	unsigned long iolen;
>> +	acpi_handle dhandle;
>> +	enum vga_switcheroo_client_id resume_client_id;
>>   
>>   	struct backlight_device *bdev;
>> -};
>> +} gmux_data;
>> +
>> +static struct pci_dev *discrete;
>> +
>> +DECLARE_COMPLETION(powerchange_done);
>>   
>>   /*
>>    * gmux port offsets. Many of these are not yet used, but may be in the
>> @@ -59,32 +69,29 @@ struct apple_gmux_data {
>>   #define GMUX_BRIGHTNESS_MASK		0x00ffffff
>>   #define GMUX_MAX_BRIGHTNESS		GMUX_BRIGHTNESS_MASK
>>   
>> -static inline u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
>> +static inline u8 gmux_read8(int port)
>>   {
>> -	return inb(gmux_data->iostart + port);
>> +	return inb(gmux_data.iostart + port);
>>   }
>>   
>> -static inline void gmux_write8(struct apple_gmux_data *gmux_data, int port,
>> -			       u8 val)
>> +static inline void gmux_write8(int port, u8 val)
>>   {
>> -	outb(val, gmux_data->iostart + port);
>> +	outb(val, gmux_data.iostart + port);
>>   }
>>   
>> -static inline u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
>> +static inline u32 gmux_read32(int port)
>>   {
>> -	return inl(gmux_data->iostart + port);
>> +	return inl(gmux_data.iostart + port);
>>   }
>>   
>>   static int gmux_get_brightness(struct backlight_device *bd)
>>   {
>> -	struct apple_gmux_data *gmux_data = bl_get_data(bd);
>> -	return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
>> +	return gmux_read32(GMUX_PORT_BRIGHTNESS) &
>>   	       GMUX_BRIGHTNESS_MASK;
>>   }
>>   
>>   static int gmux_update_status(struct backlight_device *bd)
>>   {
>> -	struct apple_gmux_data *gmux_data = bl_get_data(bd);
>>   	u32 brightness = bd->props.brightness;
>>   
>>   	if (bd->props.state & BL_CORE_SUSPENDED)
>> @@ -96,54 +103,225 @@ static int gmux_update_status(struct backlight_device *bd)
>>   	 * accept a single u32 write, but the old method also works, so we
>>   	 * just use the old method for all gmux versions.
>>   	 */
>> -	gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
>> -	gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 1, brightness >> 8);
>> -	gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 2, brightness >> 16);
>> -	gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 3, 0);
>> +	gmux_write8(GMUX_PORT_BRIGHTNESS, brightness);
>> +	gmux_write8(GMUX_PORT_BRIGHTNESS + 1, brightness >> 8);
>> +	gmux_write8(GMUX_PORT_BRIGHTNESS + 2, brightness >> 16);
>> +	gmux_write8(GMUX_PORT_BRIGHTNESS + 3, 0);
>> +
>> +	return 0;
>> +}
>> +
>> +static int gmux_switchto(enum vga_switcheroo_client_id id)
>> +{
>> +	if (id == VGA_SWITCHEROO_IGD) {
>> +		gmux_write8(GMUX_PORT_SWITCH_DDC, 1);
>> +		gmux_write8(GMUX_PORT_SWITCH_DISPLAY, 2);
>> +		gmux_write8(GMUX_PORT_SWITCH_EXTERNAL, 2);
>> +	} else {
>> +		gmux_write8(GMUX_PORT_SWITCH_DDC, 2);
>> +		gmux_write8(GMUX_PORT_SWITCH_DISPLAY, 3);
>> +		gmux_write8(GMUX_PORT_SWITCH_EXTERNAL, 3);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int gmux_call_acpi_pwrd(int arg)
>> +{
>> +	acpi_handle gfx_handle = DEVICE_ACPI_HANDLE(&discrete->dev);
>> +	acpi_handle pwrd_handle = NULL;
>> +	acpi_status status = AE_OK;
>> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
>> +	struct acpi_object_list arg_list = { 1, &arg0 };
>> +
>> +	if (!gfx_handle) {
>> +		pr_err("Cannot find device ACPI handle\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	status = acpi_get_handle(gfx_handle, "PWRD", &pwrd_handle);
>> +	if (ACPI_FAILURE(status)) {
>> +		pr_err("Cannot get PWRD handle: %s\n",
>> +		       acpi_format_exception(status));
>> +		return -ENODEV;
>> +	}
>>   
>> +	arg0.integer.value = arg;
>> +
>> +	status = acpi_evaluate_object(pwrd_handle, NULL, &arg_list, &buffer);
>> +	if (ACPI_FAILURE(status)) {
>> +		pr_err("PWRD call failed: %s\n",
>> +		       acpi_format_exception(status));
>> +		return -ENODEV;
>> +	}
>> +
>> +	kfree(buffer.pointer);
>>   	return 0;
>>   }
>>   
>> +static int gmux_set_discrete_state(enum vga_switcheroo_state state)
>> +{
>> +	/* TODO: locking for completions needed? */
>> +	init_completion(&powerchange_done);
>> +
>> +	if (state == VGA_SWITCHEROO_ON) {
>> +		gmux_call_acpi_pwrd(0);
>> +		gmux_write8(GMUX_PORT_DISCRETE_POWER, 1);
>> +		gmux_write8(GMUX_PORT_DISCRETE_POWER, 3);
>> +	} else {
>> +		gmux_write8(GMUX_PORT_DISCRETE_POWER, 1);
>> +		gmux_write8(GMUX_PORT_DISCRETE_POWER, 0);
>> +		gmux_call_acpi_pwrd(1);
>> +	}
>> +
>> +	if (wait_for_completion_interruptible_timeout(&powerchange_done,
>> +						      msecs_to_jiffies(200)))
>> +		pr_info("completion timeout\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(state);
>> +}
>> +
>> +static int gmux_init(void)
>> +{
>> +	return 0;
>> +}
>> +
>> +static int gmux_get_client_id(struct pci_dev *pdev)
>> +{
>> +	/* early mbps 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 {
>> +		discrete = pdev;
>> +		return VGA_SWITCHEROO_DIS;
>> +	}
>> +}
>> +
>> +static bool gmux_client_active(enum vga_switcheroo_client_id id)
>> +{
>> +	u8 state = gmux_read8(GMUX_PORT_SWITCH_DISPLAY);
>> +
>> +	if ((id == VGA_SWITCHEROO_IGD && state == 2) ||
>> +	    (id == VGA_SWITCHEROO_DIS && state == 3))
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>> +static struct vga_switcheroo_handler gmux_handler = {
>> +	.switchto = gmux_switchto,
>> +	.power_state = gmux_set_power_state,
>> +	.init = gmux_init,
>> +	.get_client_id = gmux_get_client_id,
>> +	.client_active = gmux_client_active,
>> +};
>> +
>> +static void gmux_disable_interrupts(void)
>> +{
>> +	gmux_write8(GMUX_PORT_INTERRUPT_ENABLE, GMUX_INTERRUPT_DISABLE);
>> +}
>> +
>> +static void gmux_enable_interrupts(void)
>> +{
>> +	gmux_write8(GMUX_PORT_INTERRUPT_ENABLE, GMUX_INTERRUPT_ENABLE);
>> +}
>> +
>> +static int gmux_interrupt_get_status(void)
>> +{
>> +	return gmux_read8(GMUX_PORT_INTERRUPT_STATUS);
>> +}
>> +
>> +static void gmux_interrupt_activate_status(void)
>> +{
>> +	int old_status;
>> +	int new_status;
>> +
>> +	/* to reactivate interrupts write back current status */
>> +	old_status = gmux_read8(GMUX_PORT_INTERRUPT_STATUS);
>> +	gmux_write8(GMUX_PORT_INTERRUPT_STATUS, old_status);
>> +	new_status = gmux_read8(GMUX_PORT_INTERRUPT_STATUS);
>> +
>> +	/* status = 0 indicates active interrupts */
>> +	if (new_status)
>> +		pr_info("gmux: error: activate_status, old_status %d new_status %d\n", old_status, new_status);
>> +}
>> +
>> +static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
>> +{
>> +	int status;
>> +
>> +	status = gmux_interrupt_get_status();
>> +	gmux_disable_interrupts();
>> +
>> +	gmux_interrupt_activate_status();
>> +	gmux_enable_interrupts();
>> +
>> +	if (status & GMUX_INTERRUPT_STATUS_POWER)
>> +		complete(&powerchange_done);
>> +}
>> +
>>   static const struct backlight_ops gmux_bl_ops = {
>>   	.options = BL_CORE_SUSPENDRESUME,
>>   	.get_brightness = gmux_get_brightness,
>>   	.update_status = gmux_update_status,
>>   };
>>   
>> +static int gmux_suspend(struct pnp_dev *dev, pm_message_t state)
>> +{
>> +	gmux_data.resume_client_id = gmux_read8(GMUX_PORT_SWITCH_DISPLAY) == 2 ?
>> +		VGA_SWITCHEROO_IGD : VGA_SWITCHEROO_DIS;
>> +	return 0;
>> +}
>> +
>> +static int gmux_resume(struct pnp_dev *dev)
>> +{
>> +	gmux_switchto(gmux_data.resume_client_id);
>> +	return 0;
>> +}
>> +
>>   static int __devinit gmux_probe(struct pnp_dev *pnp,
>>   				const struct pnp_device_id *id)
>>   {
>> -	struct apple_gmux_data *gmux_data;
>>   	struct resource *res;
>>   	struct backlight_properties props;
>>   	struct backlight_device *bdev;
>>   	u8 ver_major, ver_minor, ver_release;
>> +	acpi_status status;
>>   	int ret = -ENXIO;
>>   
>> -	gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
>> -	if (!gmux_data)
>> -		return -ENOMEM;
>> -	pnp_set_drvdata(pnp, gmux_data);
>> -
>>   	res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
>>   	if (!res) {
>>   		pr_err("Failed to find gmux I/O resource\n");
>> -		goto err_free;
>> +		goto err_begin;
>>   	}
>>   
>> -	gmux_data->iostart = res->start;
>> -	gmux_data->iolen = res->end - res->start;
>> +	gmux_data.iostart = res->start;
>> +	gmux_data.iolen = res->end - res->start;
>>   
>> -	if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
>> +	if (gmux_data.iolen < GMUX_MIN_IO_LEN) {
>>   		pr_err("gmux I/O region too small (%lu < %u)\n",
>> -		       gmux_data->iolen, GMUX_MIN_IO_LEN);
>> -		goto err_free;
>> +		       gmux_data.iolen, GMUX_MIN_IO_LEN);
>> +		goto err_begin;
>>   	}
>>   
>> -	if (!request_region(gmux_data->iostart, gmux_data->iolen,
>> +	if (!request_region(gmux_data.iostart, gmux_data.iolen,
>>   			    "Apple gmux")) {
>>   		pr_err("gmux I/O already in use\n");
>> -		goto err_free;
>> +		goto err_begin;
>>   	}
>>   
>>   	/*
>> @@ -151,9 +329,9 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
>>   	 * doesn't really have a gmux. Check for invalid version information
>>   	 * to detect this.
>>   	 */
>> -	ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
>> -	ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
>> -	ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
>> +	ver_major = gmux_read8(GMUX_PORT_VERSION_MAJOR);
>> +	ver_minor = gmux_read8(GMUX_PORT_VERSION_MINOR);
>> +	ver_release = gmux_read8(GMUX_PORT_VERSION_RELEASE);
>>   	if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
>>   		pr_info("gmux device not present\n");
>>   		ret = -ENODEV;
>> @@ -165,7 +343,7 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
>>   
>>   	memset(&props, 0, sizeof(props));
>>   	props.type = BACKLIGHT_PLATFORM;
>> -	props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
>> +	props.max_brightness = gmux_read32(GMUX_PORT_MAX_BRIGHTNESS);
>>   
>>   	/*
>>   	 * Currently it's assumed that the maximum brightness is less than
>> @@ -177,44 +355,73 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
>>   		props.max_brightness = GMUX_MAX_BRIGHTNESS;
>>   
>>   	bdev = backlight_device_register("gmux_backlight", &pnp->dev,
>> -					 gmux_data, &gmux_bl_ops, &props);
>> +					 NULL, &gmux_bl_ops, &props);
>>   	if (IS_ERR(bdev)) {
>>   		ret = PTR_ERR(bdev);
>>   		goto err_release;
>>   	}
>>   
>> -	gmux_data->bdev = bdev;
>> +	gmux_data.bdev = bdev;
>>   	bdev->props.brightness = gmux_get_brightness(bdev);
>>   	backlight_update_status(bdev);
>>   
>> -	/*
>> -	 * The backlight situation on Macs is complicated. If the gmux is
>> -	 * present it's the best choice, because it always works for
>> -	 * backlight control and supports more levels than other options.
>> -	 * Disable the other backlight choices.
>> -	 */
>> -	acpi_video_unregister();
>> -	apple_bl_unregister();
>> +	gmux_data.dhandle = DEVICE_ACPI_HANDLE(&pnp->dev);
>> +	if (!gmux_data.dhandle) {
>> +		pr_err("Cannot find acpi device for pnp device %s\n",
>> +		       dev_name(&pnp->dev));
>> +		goto err_release;
>> +	} else {
>> +		struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
>> +		acpi_get_name(gmux_data.dhandle, ACPI_SINGLE_NAME, &buf);
>> +		pr_info("Found acpi handle for pnp device %s: %s\n",
>> +			dev_name(&pnp->dev), (char *)buf.pointer);
>> +		kfree(buf.pointer);
>> +	}
>> +
>> +	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));
>> +		goto err_notify;
>> +	}
>> +
>> +	if (vga_switcheroo_register_handler(&gmux_handler))
>> +		goto err_register;
>> +
>> +	init_completion(&powerchange_done);
>> +	gmux_enable_interrupts();
>>   
>>   	return 0;
>>   
>> +err_register:
>> +	status = acpi_remove_notify_handler(gmux_data.dhandle,
>> +				     ACPI_DEVICE_NOTIFY, &gmux_notify_handler);
>> +	if (ACPI_FAILURE(status))
>> +		pr_err("Remove notify handler failed: %s\n",
>> +		       acpi_format_exception(status));
>> +err_notify:
>> +	backlight_device_unregister(bdev);
>>   err_release:
>> -	release_region(gmux_data->iostart, gmux_data->iolen);
>> -err_free:
>> -	kfree(gmux_data);
>> +	release_region(gmux_data.iostart, gmux_data.iolen);
>> +err_begin:
>>   	return ret;
>>   }
>>   
>>   static void __devexit gmux_remove(struct pnp_dev *pnp)
>>   {
>> -	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
>> -
>> -	backlight_device_unregister(gmux_data->bdev);
>> -	release_region(gmux_data->iostart, gmux_data->iolen);
>> -	kfree(gmux_data);
>> -
>> -	acpi_video_register();
>> -	apple_bl_register();
>> +	acpi_status status;
>> +
>> +	vga_switcheroo_unregister_handler();
>> +	backlight_device_unregister(gmux_data.bdev);
>> +	gmux_disable_interrupts();
>> +	status = acpi_remove_notify_handler(gmux_data.dhandle,
>> +				     ACPI_DEVICE_NOTIFY, &gmux_notify_handler);
>> +	if (ACPI_FAILURE(status))
>> +		pr_err("Remove notify handler failed: %s\n",
>> +		       acpi_format_exception(status));
>> +
>> +	release_region(gmux_data.iostart, gmux_data.iolen);
>>   }
>>   
>>   static const struct pnp_device_id gmux_device_ids[] = {
>> @@ -227,6 +434,8 @@ 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)
>>
>> -- 
>> Matthew Garrett | mjg59@...f.ucam.org


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