From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org
Subject: Re: [PATCH] ACPI: scan: Do not increase dep_unmet for already met dependencies
Date: Mon, 8 Apr 2024 16:48:46 +0200 [thread overview]
Message-ID: <CAJZ5v0iApfHiCJ-_9eLE9yuZa8RD3vQ+5aBZjpFpnzMS4+TbvQ@mail.gmail.com> (raw)
In-Reply-To: <20240406114052.4884-1-hdegoede@redhat.com>
On Sat, Apr 6, 2024 at 1:43 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> On the Toshiba Encore WT10-A tablet the BATC battery ACPI device depends
> on 3 other devices:
>
> Name (_DEP, Package (0x03) // _DEP: Dependencies
> {
> I2C1,
> GPO2,
> GPO0
> })
>
> acpi_scan_check_dep() adds all 3 of these to the acpi_dep_list and then
> before an acpi_device is created for the BATC handle (and thus before
> acpi_scan_dep_init() runs) acpi_scan_clear_dep() gets called for both
> GPIO depenencies, with free_when_met not set for the dependencies.
>
> Since there is no adev for BATC yet, there also is no dep_unmet to
> decrement. The only result of acpi_scan_clear_dep() in this case is
> dep->met getting set.
>
> Soon after acpi_scan_clear_dep() has been called for the GPIO dependencies
> the acpi_device gets created for the BATC handle and acpi_scan_dep_init()
> runs, this sees 3 dependencies on the acpi_dep_list and initializes
> unmet_dep to 3. Later when the dependency for I2C1 is met unmet_dep
> becomes 2, but since the 2 GPIO deps where already met it never becomes 0
> causing battery monitoring to not work.
>
> Fix this by modifying acpi_scan_dep_init() to not increase dep_met for
> dependencies which have already been marked as being met.
>
> Fixes: 3ba12d8de3fa ("ACPI: scan: Reduce overhead related to devices with dependencies")
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/acpi/scan.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 7c157bf92695..d1464324de95 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1843,7 +1843,8 @@ static void acpi_scan_dep_init(struct acpi_device *adev)
> if (dep->honor_dep)
> adev->flags.honor_deps = 1;
>
> - adev->dep_unmet++;
> + if (!dep->met)
> + adev->dep_unmet++;
Nice catch!
> }
> }
> }
> --
Applied as 6.9-rc material, thanks!
prev parent reply other threads:[~2024-04-08 14:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-06 11:40 [PATCH] ACPI: scan: Do not increase dep_unmet for already met dependencies Hans de Goede
2024-04-08 14:48 ` Rafael J. Wysocki [this message]
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