Re: [PATCH] ACPI / GED: unregister interrupts during shutdown

From: Rafael J. Wysocki
Date: Tue Dec 05 2017 - 17:18:52 EST


On Tue, Dec 5, 2017 at 10:01 PM, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:
> Some GED interrupts could be pending by the time we are doing a reboot.
>
> Even though GED driver uses devm_request_irq() to register the interrupt
> handler, the handler is not being freed on time during a shutdown since
> the driver is missing a shutdown callback.
>
> If the ACPI handler is no longer available, this causes an interrupt
> storm and delays shutdown.
>
> Register a shutdown callback and manually free the interrupts.
>
> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/evged.c | 36 +++++++++++++++++++++++++++++++++---
> 1 file changed, 33 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c
> index 46f0603..dde50ea 100644
> --- a/drivers/acpi/evged.c
> +++ b/drivers/acpi/evged.c
> @@ -1,7 +1,7 @@
> /*
> * Generic Event Device for ACPI.
> *
> - * Copyright (c) 2016, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2016-2017, The Linux Foundation. All rights reserved.

Why are you changing this?

> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License version 2 and
> @@ -49,6 +49,11 @@
>
> #define MODULE_NAME "acpi-ged"
>
> +struct acpi_ged_device {
> + struct device *dev;
> + struct list_head event_list;
> +};
> +
> struct acpi_ged_event {
> struct list_head node;
> struct device *dev;
> @@ -76,7 +81,8 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
> unsigned int irq;
> unsigned int gsi;
> unsigned int irqflags = IRQF_ONESHOT;
> - struct device *dev = context;
> + struct acpi_ged_device *geddev = context;
> + struct device *dev = geddev->dev;
> acpi_handle handle = ACPI_HANDLE(dev);
> acpi_handle evt_handle;
> struct resource r;
> @@ -122,29 +128,53 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
> return AE_ERROR;
> }
>
> + dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);

Why dev_info()?

> + list_add_tail(&event->node, &geddev->event_list);
> return AE_OK;
> }
>
> static int ged_probe(struct platform_device *pdev)
> {
> + struct acpi_ged_device *geddev;
> acpi_status acpi_ret;
>
> + geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL);
> + if (!geddev)
> + return -ENOMEM;
> +
> + geddev->dev = &pdev->dev;
> + INIT_LIST_HEAD(&geddev->event_list);
> acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
> - acpi_ged_request_interrupt, &pdev->dev);
> + acpi_ged_request_interrupt, geddev);
> if (ACPI_FAILURE(acpi_ret)) {
> dev_err(&pdev->dev, "unable to parse the _CRS record\n");
> return -EINVAL;
> }
> + platform_set_drvdata(pdev, geddev);
>
> return 0;
> }
>
> +static void ged_remove(struct platform_device *pdev)
> +{
> + struct acpi_ged_device *geddev = platform_get_drvdata(pdev);
> + struct acpi_ged_event *event, *next;
> +
> + list_for_each_entry_safe(event, next, &geddev->event_list, node) {
> + devm_free_irq(geddev->dev, event->irq, event);
> + list_del(&event->node);
> + dev_info(geddev->dev, "GED releasing GSI %u @ IRQ %u\n",
> + event->gsi, event->irq);

dev_dbg() and that if you really need it.

> + }
> +}
> +
> static const struct acpi_device_id ged_acpi_ids[] = {
> {"ACPI0013"},
> {},
> };
>
> static struct platform_driver ged_driver = {
> + .shutdown = ged_remove,

That ged_remove really should be called ged_shutdown. It is confusing
as is, because there is a ->remove callback in the structure too.

> .probe = ged_probe,
> .driver = {
> .name = MODULE_NAME,
> --

Overall, it looks like we should just unbind the driver from all
devices on shutdown.

Thanks,
Rafael