From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>,
Linus Walleij <linus.walleij@linaro.org>,
linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] pinctrl: cherryview: Ensure _REG(ACPI_ADR_SPACE_GPIO, 1) gets called
Date: Wed, 29 Apr 2020 17:21:59 +0300 [thread overview]
Message-ID: <20200429142159.GJ185537@smile.fi.intel.com> (raw)
In-Reply-To: <20200429104651.63643-1-hdegoede@redhat.com>
On Wed, Apr 29, 2020 at 12:46:51PM +0200, Hans de Goede wrote:
> On Cherry Trail devices there are 2 possible ACPI OpRegions for
> accessing GPIOs. The standard GeneralPurposeIo OpRegion and the Cherry
> Trail specific UserDefined 0x9X OpRegions.
>
> Having 2 different types of OpRegions leads to potential issues with
> checks for OpRegion availability, or in other words checks if _REG has
> been called for the OpRegion which the ACPI code wants to use.
>
> The ACPICA core does not call _REG on an ACPI node which does not
> define an OpRegion matching the type being registered; and the reference
> design DSDT, from which most Cherry Trail DSDTs are derived, does not
> define GeneralPurposeIo, nor UserDefined(0x93) OpRegions for the GPO2
> (UID 3) device, because no pins were assigned ACPI controlled functions
> in the reference design.
>
> Together this leads to the perfect storm, at least on the Cherry Trail
> based Medion Akayo E1239T. This design does use a GPO2 pin from its ACPI
> code and has added the Cherry Trail specific UserDefined(0x93) opregion
> to its GPO2 ACPI node to access this pin.
>
> But it uses a has _REG been called availability check for the standard
> GeneralPurposeIo OpRegion. This clearly is a bug in the DSDT, but this
> does work under Windows. This issue leads to the intel_vbtn driver
> reporting the device always being in tablet-mode at boot, even if it
> is in laptop mode. Which in turn causes userspace to ignore touchpad
> events. So iow this issues causes the touchpad to not work at boot.
>
> Since the bug in the DSDT stems from the confusion of having 2 different
> OpRegion types for accessing GPIOs on Cherry Trail devices, I believe
> that this is best fixed inside the cherryview pinctrl driver.
>
> This commit adds a workaround to the cherryview pinctrl driver so
> that the DSDT's expectations of _REG always getting called for the
> GeneralPurposeIo OpRegion are met.
s/cherryview/Cherryview/g
...
> + if (acpi_has_method(adev->handle, "_REG")) {
And this check si redundant, you may call it as is (you didn't check for error
anyway), see also below.
> + struct acpi_object_list input;
> + union acpi_object params[2];
> +
> + input.count = 2;
> + input.pointer = params;
> + params[0].type = ACPI_TYPE_INTEGER;
> + params[0].integer.value = ACPI_ADR_SPACE_GPIO;
> + params[1].type = ACPI_TYPE_INTEGER;
> + params[1].integer.value = 1;
> + acpi_evaluate_object(adev->handle, "_REG", &input, NULL);
> + }
Can you consider to unify this with one in drivers/pci/hotplug/acpiphp_glue.c,
so we will have some helper function at the end? (perhaps as separate changes
to make less burden on backporting this one)
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-04-29 14:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 10:46 [PATCH] pinctrl: cherryview: Ensure _REG(ACPI_ADR_SPACE_GPIO, 1) gets called Hans de Goede
2020-04-29 14:21 ` Andy Shevchenko [this message]
2020-05-04 14:55 ` Hans de Goede
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