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Code Issues Releases Packages Activity

gpio: acpi: Even more tighten up ACPI GPIO lookups

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The commit 10cf4899f8 ("gpiolib: tighten up ACPI legacy gpio lookups")
prevents to getting same resource twice if the driver asks twice using
different connection ID.

But the whole idea of fallback might bring some problems. Imagine the case when
we have two versions of BIOS/hardware where in one _DSD is introduced along
with GPIO resources, but the other one uses just plain GPIO resource for
another purpose

Case 1:

    Device (DEVX)
    {
        ...
        Name (_CRS, ResourceTemplate ()
        {
            GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly,
                    "\\_SB.GPO0", 0, ResourceConsumer) {15}
        })
        Name (_DSD, Package ()
        {
            ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
            Package ()
            {
                Package () {"some-gpios", Package() {^DEVX, 0, 0, 0 }},
            }
        })
    }

Case 2:

    Device (DEVX)
    {
        ...
        Name (_CRS, ResourceTemplate ()
        {
            GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly,
                    "\\_SB.GPO0", 0, ResourceConsumer) {27}
        })
    }

To prevent the possible misconfiguration tighten up even more GPIO ACPI lookups
for case without connection ID provided.

In the past the issue had been triggered by "use mctrl_gpio helpers" series
[1,2].

[1] commit 4ef03d3287 ("tty/serial/8250: use mctrl_gpio helpers")
[2] https://patchwork.kernel.org/patch/9283745/

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Andy Shevchenko 2017-05-23 20:03:19 +03:00 • committed by Linus Walleij
commit f10e4bf663
1 changed files with 1 additions and 35 deletions
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