linux-kernel - Re: [PATCH v3 1/4] ACPI / scan: Fix acpi_is_indirect_io

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Date:   Tue, 7 Aug 2018 11:05:13 +0100
From:   John Garry <john.garry@...wei.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Darren Hart <dvhart@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>
CC:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        <linux-acpi@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        <linux-i2c@...r.kernel.org>, <stable@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Dann Frazier <dann.frazier@...onical.com>,
        Linuxarm <linuxarm@...wei.com>
Subject: Re: [PATCH v3 1/4] ACPI / scan: Fix acpi_is_indirect_io_slave()
 always returning false

On 07/08/2018 09:05, Hans de Goede wrote:
> Since commit 63347db0affa ("ACPI / scan: Use acpi_bus_get_status() to
> initialize ACPI_TYPE_DEVICE devs") the status field of normal acpi_devices
> gets set to 0 by acpi_bus_type_and_status() and filled with its actual
> value later when acpi_add_single_object() calls acpi_bus_get_status().
>
> This means that status is 0 when acpi_device_enumeration_by_parent()
> gets called which makes the acpi_match_device_ids() call in
> acpi_is_indirect_io_slave() always return -ENOENT.

For for the (child) device the status may be zero, but how about the 
parent device (which is what we care about)? As I see, we would have set 
the parent device status present field at this stage.

Thanks,
John

>
> This commit fixes this by making acpi_bus_type_and_status() set status to
> ACPI_STA_DEFAULT until acpi_add_single_object() calls acpi_bus_get_status()
>
> Fixes: dfda4492322e ("ACPI / scan: Do not enumerate Indirect IO host children")
> Cc: stable@...r.kernel.org
> Cc: John Garry <john.garry@...wei.com>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: Dann Frazier <dann.frazier@...onical.com>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
>  drivers/acpi/scan.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 970dd87d347c..6799d00dd790 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1612,7 +1612,8 @@ static int acpi_add_single_object(struct acpi_device **child,
>  	 * Note this must be done before the get power-/wakeup_dev-flags calls.
>  	 */
>  	if (type == ACPI_BUS_TYPE_DEVICE)
> -		acpi_bus_get_status(device);
> +		if (acpi_bus_get_status(device) < 0)
> +			acpi_set_device_status(device, 0);
>
>  	acpi_bus_get_power_flags(device);
>  	acpi_bus_get_wakeup_device_flags(device);
> @@ -1690,7 +1691,7 @@ static int acpi_bus_type_and_status(acpi_handle handle, int *type,
>  		 * acpi_add_single_object updates this once we've an acpi_device
>  		 * so that acpi_bus_get_status' quirk handling can be used.
>  		 */
> -		*sta = 0;
> +		*sta = ACPI_STA_DEFAULT;
>  		break;
>  	case ACPI_TYPE_PROCESSOR:
>  		*type = ACPI_BUS_TYPE_PROCESSOR;
>