linux/drivers/acpi/glue.c
Hans de Goede f64e4275ef ACPI: Fix selecting wrong ACPI fwnode for the iGPU on some Dell laptops
The Dell Latitude E6430 both with and without the optional NVidia dGPU
has a bug in its ACPI tables which is causing Linux to assign the wrong
ACPI fwnode / companion to the pci_device for the i915 iGPU.

Specifically under the PCI root bridge there are these 2 ACPI Device()s :

 Scope (_SB.PCI0)
 {
     Device (GFX0)
     {
         Name (_ADR, 0x00020000)  // _ADR: Address
     }

     ...

     Device (VID)
     {
         Name (_ADR, 0x00020000)  // _ADR: Address
         ...

         Method (_DOS, 1, NotSerialized)  // _DOS: Disable Output Switching
         {
             VDP8 = Arg0
             VDP1 (One, VDP8)
         }

         Method (_DOD, 0, NotSerialized)  // _DOD: Display Output Devices
         {
             ...
         }
         ...
     }
 }

The non-functional GFX0 ACPI device is a problem, because this gets
returned as ACPI companion-device by acpi_find_child_device() for the iGPU.

This is a long standing problem and the i915 driver does use the ACPI
companion for some things, but works fine without it.

However since commit 63f534b8ba ("ACPI: PCI: Rework acpi_get_pci_dev()")
acpi_get_pci_dev() relies on the physical-node pointer in the acpi_device
and that is set on the wrong acpi_device because of the wrong
acpi_find_child_device() return. This breaks the ACPI video code,
leading to non working backlight control in some cases.

Add a type.backlight flag, mark ACPI video bus devices with this and make
find_child_checks() return a higher score for children with this flag set,
so that it picks the right companion-device.

Fixes: 63f534b8ba ("ACPI: PCI: Rework acpi_get_pci_dev()")
Co-developed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: 6.1+ <stable@vger.kernel.org> # 6.1+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2023-01-10 20:23:48 +01:00

415 lines
9.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Link physical devices with ACPI devices support
*
* Copyright (c) 2005 David Shaohua Li <shaohua.li@intel.com>
* Copyright (c) 2005 Intel Corp.
*/
#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/acpi_iort.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/platform_device.h>
#include "internal.h"
static LIST_HEAD(bus_type_list);
static DECLARE_RWSEM(bus_type_sem);
#define PHYSICAL_NODE_STRING "physical_node"
#define PHYSICAL_NODE_NAME_SIZE (sizeof(PHYSICAL_NODE_STRING) + 10)
int register_acpi_bus_type(struct acpi_bus_type *type)
{
if (acpi_disabled)
return -ENODEV;
if (type && type->match && type->find_companion) {
down_write(&bus_type_sem);
list_add_tail(&type->list, &bus_type_list);
up_write(&bus_type_sem);
pr_info("bus type %s registered\n", type->name);
return 0;
}
return -ENODEV;
}
EXPORT_SYMBOL_GPL(register_acpi_bus_type);
int unregister_acpi_bus_type(struct acpi_bus_type *type)
{
if (acpi_disabled)
return 0;
if (type) {
down_write(&bus_type_sem);
list_del_init(&type->list);
up_write(&bus_type_sem);
pr_info("bus type %s unregistered\n", type->name);
return 0;
}
return -ENODEV;
}
EXPORT_SYMBOL_GPL(unregister_acpi_bus_type);
static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
{
struct acpi_bus_type *tmp, *ret = NULL;
down_read(&bus_type_sem);
list_for_each_entry(tmp, &bus_type_list, list) {
if (tmp->match(dev)) {
ret = tmp;
break;
}
}
up_read(&bus_type_sem);
return ret;
}
#define FIND_CHILD_MIN_SCORE 1
#define FIND_CHILD_MID_SCORE 2
#define FIND_CHILD_MAX_SCORE 3
static int match_any(struct acpi_device *adev, void *not_used)
{
return 1;
}
static bool acpi_dev_has_children(struct acpi_device *adev)
{
return acpi_dev_for_each_child(adev, match_any, NULL) > 0;
}
static int find_child_checks(struct acpi_device *adev, bool check_children)
{
unsigned long long sta;
acpi_status status;
if (check_children && !acpi_dev_has_children(adev))
return -ENODEV;
status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
if (status == AE_NOT_FOUND) {
/*
* Special case: backlight device objects without _STA are
* preferred to other objects with the same _ADR value, because
* it is more likely that they are actually useful.
*/
if (adev->pnp.type.backlight)
return FIND_CHILD_MID_SCORE;
return FIND_CHILD_MIN_SCORE;
}
if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
return -ENODEV;
/*
* If the device has a _HID returning a valid ACPI/PNP device ID, it is
* better to make it look less attractive here, so that the other device
* with the same _ADR value (that may not have a valid device ID) can be
* matched going forward. [This means a second spec violation in a row,
* so whatever we do here is best effort anyway.]
*/
if (adev->pnp.type.platform_id)
return FIND_CHILD_MIN_SCORE;
return FIND_CHILD_MAX_SCORE;
}
struct find_child_walk_data {
struct acpi_device *adev;
u64 address;
int score;
bool check_sta;
bool check_children;
};
static int check_one_child(struct acpi_device *adev, void *data)
{
struct find_child_walk_data *wd = data;
int score;
if (!adev->pnp.type.bus_address || acpi_device_adr(adev) != wd->address)
return 0;
if (!wd->adev) {
/*
* This is the first matching object, so save it. If it is not
* necessary to look for any other matching objects, stop the
* search.
*/
wd->adev = adev;
return !(wd->check_sta || wd->check_children);
}
/*
* There is more than one matching device object with the same _ADR
* value. That really is unexpected, so we are kind of beyond the scope
* of the spec here. We have to choose which one to return, though.
*
* First, get the score for the previously found object and terminate
* the walk if it is maximum.
*/
if (!wd->score) {
score = find_child_checks(wd->adev, wd->check_children);
if (score == FIND_CHILD_MAX_SCORE)
return 1;
wd->score = score;
}
/*
* Second, if the object that has just been found has a better score,
* replace the previously found one with it and terminate the walk if
* the new score is maximum.
*/
score = find_child_checks(adev, wd->check_children);
if (score > wd->score) {
wd->adev = adev;
if (score == FIND_CHILD_MAX_SCORE)
return 1;
wd->score = score;
}
/* Continue, because there may be better matches. */
return 0;
}
static struct acpi_device *acpi_find_child(struct acpi_device *parent,
u64 address, bool check_children,
bool check_sta)
{
struct find_child_walk_data wd = {
.address = address,
.check_children = check_children,
.check_sta = check_sta,
.adev = NULL,
.score = 0,
};
if (parent)
acpi_dev_for_each_child(parent, check_one_child, &wd);
return wd.adev;
}
struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
u64 address, bool check_children)
{
return acpi_find_child(parent, address, check_children, true);
}
EXPORT_SYMBOL_GPL(acpi_find_child_device);
struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
acpi_bus_address adr)
{
return acpi_find_child(adev, adr, false, false);
}
EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);
static void acpi_physnode_link_name(char *buf, unsigned int node_id)
{
if (node_id > 0)
snprintf(buf, PHYSICAL_NODE_NAME_SIZE,
PHYSICAL_NODE_STRING "%u", node_id);
else
strcpy(buf, PHYSICAL_NODE_STRING);
}
int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
{
struct acpi_device_physical_node *physical_node, *pn;
char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
struct list_head *physnode_list;
unsigned int node_id;
int retval = -EINVAL;
if (has_acpi_companion(dev)) {
if (acpi_dev) {
dev_warn(dev, "ACPI companion already set\n");
return -EINVAL;
} else {
acpi_dev = ACPI_COMPANION(dev);
}
}
if (!acpi_dev)
return -EINVAL;
acpi_dev_get(acpi_dev);
get_device(dev);
physical_node = kzalloc(sizeof(*physical_node), GFP_KERNEL);
if (!physical_node) {
retval = -ENOMEM;
goto err;
}
mutex_lock(&acpi_dev->physical_node_lock);
/*
* Keep the list sorted by node_id so that the IDs of removed nodes can
* be recycled easily.
*/
physnode_list = &acpi_dev->physical_node_list;
node_id = 0;
list_for_each_entry(pn, &acpi_dev->physical_node_list, node) {
/* Sanity check. */
if (pn->dev == dev) {
mutex_unlock(&acpi_dev->physical_node_lock);
dev_warn(dev, "Already associated with ACPI node\n");
kfree(physical_node);
if (ACPI_COMPANION(dev) != acpi_dev)
goto err;
put_device(dev);
acpi_dev_put(acpi_dev);
return 0;
}
if (pn->node_id == node_id) {
physnode_list = &pn->node;
node_id++;
}
}
physical_node->node_id = node_id;
physical_node->dev = dev;
list_add(&physical_node->node, physnode_list);
acpi_dev->physical_node_count++;
if (!has_acpi_companion(dev))
ACPI_COMPANION_SET(dev, acpi_dev);
acpi_physnode_link_name(physical_node_name, node_id);
retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
physical_node_name);
if (retval)
dev_err(&acpi_dev->dev, "Failed to create link %s (%d)\n",
physical_node_name, retval);
retval = sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj,
"firmware_node");
if (retval)
dev_err(dev, "Failed to create link firmware_node (%d)\n",
retval);
mutex_unlock(&acpi_dev->physical_node_lock);
if (acpi_dev->wakeup.flags.valid)
device_set_wakeup_capable(dev, true);
return 0;
err:
ACPI_COMPANION_SET(dev, NULL);
put_device(dev);
acpi_dev_put(acpi_dev);
return retval;
}
EXPORT_SYMBOL_GPL(acpi_bind_one);
int acpi_unbind_one(struct device *dev)
{
struct acpi_device *acpi_dev = ACPI_COMPANION(dev);
struct acpi_device_physical_node *entry;
if (!acpi_dev)
return 0;
mutex_lock(&acpi_dev->physical_node_lock);
list_for_each_entry(entry, &acpi_dev->physical_node_list, node)
if (entry->dev == dev) {
char physnode_name[PHYSICAL_NODE_NAME_SIZE];
list_del(&entry->node);
acpi_dev->physical_node_count--;
acpi_physnode_link_name(physnode_name, entry->node_id);
sysfs_remove_link(&acpi_dev->dev.kobj, physnode_name);
sysfs_remove_link(&dev->kobj, "firmware_node");
ACPI_COMPANION_SET(dev, NULL);
/* Drop references taken by acpi_bind_one(). */
put_device(dev);
acpi_dev_put(acpi_dev);
kfree(entry);
break;
}
mutex_unlock(&acpi_dev->physical_node_lock);
return 0;
}
EXPORT_SYMBOL_GPL(acpi_unbind_one);
void acpi_device_notify(struct device *dev)
{
struct acpi_device *adev;
int ret;
ret = acpi_bind_one(dev, NULL);
if (ret) {
struct acpi_bus_type *type = acpi_get_bus_type(dev);
if (!type)
goto err;
adev = type->find_companion(dev);
if (!adev) {
dev_dbg(dev, "ACPI companion not found\n");
goto err;
}
ret = acpi_bind_one(dev, adev);
if (ret)
goto err;
if (type->setup) {
type->setup(dev);
goto done;
}
} else {
adev = ACPI_COMPANION(dev);
if (dev_is_pci(dev)) {
pci_acpi_setup(dev, adev);
goto done;
} else if (dev_is_platform(dev)) {
acpi_configure_pmsi_domain(dev);
}
}
if (adev->handler && adev->handler->bind)
adev->handler->bind(dev);
done:
acpi_handle_debug(ACPI_HANDLE(dev), "Bound to device %s\n",
dev_name(dev));
return;
err:
dev_dbg(dev, "No ACPI support\n");
}
void acpi_device_notify_remove(struct device *dev)
{
struct acpi_device *adev = ACPI_COMPANION(dev);
if (!adev)
return;
if (dev_is_pci(dev))
pci_acpi_cleanup(dev, adev);
else if (adev->handler && adev->handler->unbind)
adev->handler->unbind(dev);
acpi_unbind_one(dev);
}