Initial conversion to a PCI device using runtime PM
bbswitch will now bind a driver to the PCI device, this should remove races that can occur when a PCI device is removed after bbswitch is loaded. Fixes: - Fixed a crash on some laptops that trigger a hotplug (a problem since Linux 3.12, https://github.com/Bumblebee-Project/bbswitch/issues/100) - As a driver is bound, you cannot "accidentally" load nouveau/nvidia anymore and confuse the power state. Removed pci_set_master, there is no need for access to the PCI BARs. pci_enable_device is removed too as the memory regions are not needed. TODO: - Remove unload_state, it is a no-op. - Update load_state doc (assume ON by default). - System suspend/resume probably needs special treatment to ensure that the device is off again.
This commit is contained in:
parent
ca16c538fd
commit
5c7b3f53f2
243
bbswitch.c
243
bbswitch.c
@ -35,6 +35,7 @@
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#include <linux/suspend.h>
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#include <linux/seq_file.h>
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#include <linux/pm_runtime.h>
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#include <linux/pm_domain.h>
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#include <linux/version.h>
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#if LINUX_VERSION_CODE < KERNEL_VERSION(3,8,0)
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@ -93,9 +94,14 @@ static int dsm_type = DSM_TYPE_UNSUPPORTED;
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/* The cached name of the discrete device (of the form "0000:01:00.0"). */
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static char dis_dev_name[16];
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/* dis_dev is non-NULL iff it is currently bound by bbswitch (and off). */
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static struct pci_dev *dis_dev;
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static acpi_handle dis_handle;
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/* The PM domain that wraps the PCI device, used to ensure that power is
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* available before the device is put in D0. ("Nvidia" DSM and PR3). */
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static struct dev_pm_domain pm_domain;
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static char *buffer_to_string(const char *buffer, size_t n, char *target) {
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int i;
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for (i=0; i<n; i++) {
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@ -233,82 +239,167 @@ static int bbswitch_acpi_on(void) {
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// Returns 1 if the card is disabled, 0 if enabled
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static int is_card_disabled(void) {
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u32 cfg_word;
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// read first config word which contains Vendor and Device ID. If all bits
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// are enabled, the device is assumed to be off
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pci_read_config_dword(dis_dev, 0, &cfg_word);
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// if one of the bits is not enabled (the card is enabled), the inverted
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// result will be non-zero and hence logical not will make it 0 ("false")
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return !~cfg_word;
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/* Assume that the device is disabled when our PCI driver found a device. */
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return dis_dev != NULL;
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}
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static void bbswitch_off(void) {
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if (is_card_disabled())
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return;
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// to prevent the system from possibly locking up, don't disable the device
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// if it's still in use by a driver (i.e. nouveau or nvidia)
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if (dis_dev->driver) {
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pr_warn("device %s is in use by driver '%s', refusing OFF\n",
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dev_name(&dis_dev->dev), dis_dev->driver->name);
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return;
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/* Power source handling. */
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static int bbswitch_pmd_runtime_suspend(struct device *dev)
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{
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int ret;
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pr_debug("Preparing for runtime suspend.\n");
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/* Put the device in D3. */
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ret = dev->bus->pm->runtime_suspend(dev);
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if (ret)
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return ret;
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bbswitch_acpi_off();
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/* TODO For PR3, disable them. */
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return 0;
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}
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static int bbswitch_pmd_runtime_resume(struct device *dev)
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{
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pr_info("enabling discrete graphics\n");
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bbswitch_acpi_on();
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/* TODO For PR3, enable them. */
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/* Now ensure that the device is actually put in D0 by PCI. */
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return dev->bus->pm->runtime_resume(dev);
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}
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static void bbswitch_pmd_set(struct device *dev)
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{
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pm_domain.ops = *dev->bus->pm;
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pm_domain.ops.runtime_resume = bbswitch_pmd_runtime_resume;
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pm_domain.ops.runtime_suspend = bbswitch_pmd_runtime_suspend;
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dev_pm_domain_set(dev, &pm_domain);
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}
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/* Nvidia device itself. */
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static int bbswitch_pci_runtime_suspend(struct device *dev)
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{
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struct pci_dev *pdev = to_pci_dev(dev);
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pr_info("disabling discrete graphics\n");
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if (bbswitch_optimus_dsm()) {
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pr_warn("Optimus ACPI call failed, the device is not disabled\n");
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bbswitch_optimus_dsm();
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/* Save state now that the device is still awake, makes PCI layer happy */
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pci_save_state(pdev);
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/* TODO if _PR3 is supported, should this be PCI_D3hot? */
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pci_set_power_state(pdev, PCI_D3hot);
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return 0;
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}
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static int bbswitch_pci_runtime_resume(struct device *dev)
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{
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pr_debug("Finishing runtime resume.\n");
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return 0;
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}
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static const struct dev_pm_ops bbswitch_pci_pm_ops = {
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.runtime_suspend = bbswitch_pci_runtime_suspend,
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.runtime_resume = bbswitch_pci_runtime_resume,
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/* No runtime_idle callback, the default zero delay is sufficient. */
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};
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static int bbswitch_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
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{
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/* Only bind to the device which we discovered before. */
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if (strcmp(dev_name(&pdev->dev), dis_dev_name))
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return -ENODEV;
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pr_debug("Found PCI device\n");
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dis_dev = pdev;
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bbswitch_pmd_set(&pdev->dev);
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/* Prevent kernel from detaching the PCI device for some devices that
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* generate hotplug events. The graphics card is typically not physically
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* removable. */
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pci_ignore_hotplug(pdev);
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pm_runtime_set_active(&pdev->dev); /* clear any errors */
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/* Use autosuspend to avoid lspci waking up the device multiple times. */
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pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
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pm_runtime_use_autosuspend(&pdev->dev);
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pm_runtime_allow(&pdev->dev);
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pm_runtime_put_autosuspend(&pdev->dev);
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return 0;
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}
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static void bbswitch_pci_remove(struct pci_dev *pdev)
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{
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pr_debug("Removing PCI device\n");
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pm_runtime_get_noresume(&pdev->dev);
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pm_runtime_dont_use_autosuspend(&pdev->dev);
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pm_runtime_forbid(&pdev->dev);
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dev_pm_domain_set(&pdev->dev, NULL);
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dis_dev = NULL;
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}
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static const struct pci_device_id pciidlist[] = {
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{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID),
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PCI_CLASS_DISPLAY_VGA << 8, 0xffff00 },
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{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID),
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PCI_CLASS_DISPLAY_3D << 8, 0xffff00 },
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{ 0, 0, 0 },
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};
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static struct pci_driver bbswitch_pci_driver = {
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.name = KBUILD_MODNAME,
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.id_table = pciidlist,
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.probe = bbswitch_pci_probe,
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.remove = bbswitch_pci_remove,
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.driver.pm = &bbswitch_pci_pm_ops,
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};
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static void bbswitch_off(void) {
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int ret;
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/* Do nothing if the device was disabled before. */
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if (dis_dev)
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return;
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ret = pci_register_driver(&bbswitch_pci_driver);
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if (ret) {
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pr_warn("Cannot register PCI device\n");
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return;
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}
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pci_save_state(dis_dev);
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pci_clear_master(dis_dev);
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pci_disable_device(dis_dev);
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do {
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struct acpi_device *ad = NULL;
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int r;
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/* If the probe failed, remove the driver such that it can be reprobed on
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* the next registration. */
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if (!dis_dev) {
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#if 0
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/* TODO discover the other driver name if possible. */
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pr_warn("device %s is in use by driver '%s', refusing OFF\n",
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dev_name(&dis_dev->dev), dis_dev->driver->name);
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#endif
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r = acpi_bus_get_device(dis_handle, &ad);
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if (r || !ad) {
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pr_warn("Cannot get ACPI device for PCI device\n");
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break;
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pr_warn("Could not bind to device, is it in use by an other driver?\n");
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pci_unregister_driver(&bbswitch_pci_driver);
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}
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if (ad->power.state == ACPI_STATE_UNKNOWN) {
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pr_debug("ACPI power state is unknown, forcing D0\n");
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ad->power.state = ACPI_STATE_D0;
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}
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} while (0);
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pci_set_power_state(dis_dev, PCI_D3cold);
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if (bbswitch_acpi_off())
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pr_warn("The discrete card could not be disabled by a _DSM call\n");
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}
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static void bbswitch_on(void) {
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if (!is_card_disabled())
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/* Do nothing if no device exists that was previously disabled. */
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if (!dis_dev)
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return;
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pr_info("enabling discrete graphics\n");
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if (bbswitch_acpi_on())
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pr_warn("The discrete card could not be enabled by a _DSM call\n");
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pci_set_power_state(dis_dev, PCI_D0);
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pci_restore_state(dis_dev);
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if (pci_enable_device(dis_dev))
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pr_warn("failed to enable %s\n", dev_name(&dis_dev->dev));
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pci_set_master(dis_dev);
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}
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/* power bus so we can read PCI configuration space */
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static void dis_dev_get(void) {
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if (dis_dev->bus && dis_dev->bus->self)
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pm_runtime_get_sync(&dis_dev->bus->self->dev);
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}
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static void dis_dev_put(void) {
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if (dis_dev->bus && dis_dev->bus->self)
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pm_runtime_put_sync(&dis_dev->bus->self->dev);
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pci_unregister_driver(&bbswitch_pci_driver);
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}
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static ssize_t bbswitch_proc_write(struct file *fp, const char __user *buff,
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@ -321,25 +412,19 @@ static ssize_t bbswitch_proc_write(struct file *fp, const char __user *buff,
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if (copy_from_user(cmd, buff, len))
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return -EFAULT;
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dis_dev_get();
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if (strncmp(cmd, "OFF", 3) == 0)
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bbswitch_off();
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if (strncmp(cmd, "ON", 2) == 0)
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bbswitch_on();
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dis_dev_put();
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return len;
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}
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static int bbswitch_proc_show(struct seq_file *seqfp, void *p) {
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// show the card state. Example output: 0000:01:00:00 ON
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dis_dev_get();
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seq_printf(seqfp, "%s %s\n", dis_dev_name,
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is_card_disabled() ? "OFF" : "ON");
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dis_dev_put();
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return 0;
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}
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static int bbswitch_proc_open(struct inode *inode, struct file *file) {
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@ -385,7 +470,6 @@ static int __init bbswitch_init(void) {
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dev_name(&pdev->dev), (char *)buf.pointer);
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} else {
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strlcpy(dis_dev_name, dev_name(&pdev->dev), sizeof(dis_dev_name));
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dis_dev = pdev;
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dis_handle = handle;
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pr_info("Found discrete VGA device %s: %s\n",
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dev_name(&pdev->dev), (char *)buf.pointer);
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@ -393,7 +477,7 @@ static int __init bbswitch_init(void) {
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kfree(buf.pointer);
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}
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if (dis_dev == NULL) {
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if (dis_handle == NULL) {
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pr_err("No discrete VGA device found\n");
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return -ENODEV;
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}
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@ -425,41 +509,20 @@ static int __init bbswitch_init(void) {
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return -ENOMEM;
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}
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dis_dev_get();
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if (!is_card_disabled()) {
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/* We think the card is enabled, so ensure the kernel does as well */
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if (pci_enable_device(dis_dev))
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pr_warn("failed to enable %s\n", dev_name(&dis_dev->dev));
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}
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if (load_state == CARD_ON)
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bbswitch_on();
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else if (load_state == CARD_OFF)
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if (load_state == CARD_OFF)
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bbswitch_off();
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pr_info("Succesfully loaded. Discrete card %s is %s\n",
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dis_dev_name, is_card_disabled() ? "off" : "on");
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dis_dev_put();
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return 0;
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}
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static void __exit bbswitch_exit(void) {
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remove_proc_entry("bbswitch", acpi_root_dir);
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dis_dev_get();
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if (unload_state == CARD_ON)
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bbswitch_on();
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else if (unload_state == CARD_OFF)
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bbswitch_off();
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pr_info("Unloaded. Discrete card %s is %s\n",
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dev_name(&dis_dev->dev), is_card_disabled() ? "off" : "on");
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dis_dev_put();
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pr_info("Unloaded\n");
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}
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module_init(bbswitch_init);
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