Date:   Thu, 25 Jul 2019 20:33:25 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Ayman Bagabas <ayman.bagabas@...il.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 0/9] platform/x86: Huawei WMI laptop extras driver

On Sun, Jun 30, 2019 at 8:41 AM Ayman Bagabas <ayman.bagabas@...il.com> wrote:
>
> This patch series introduce changes to huawei-wmi driver that includes:
> * Move to platform driver
> * Implement WMI management interface
> * Add micmute LED support through WMI
> * Add battery charging protection support through WMI
> * Add fn-lock support through WMI
> * Implement driver quirks and parameters
> * Add a debugfs interface to WMI
>
> # Move to platform driver
>
> The current driver offers hotkeys and micmute led support only. With
> these changes, a platform driver makes more sense since it handles these
> changes pretty nicely.
>
> # Implement WMI management interface
>
> Huawei Matebook laptops come with two WMI interfaces. The first being
> WMI0 which is considered "legacy" and AFAIK only found on the Matebook X
> released in 2017. The second has a UID of "HWMI" and is found in pretty
> much all models with a slight difference in implementation except for
> the Matebook X (2017). Since this model has two interfaces, some aspects
> are controlled through the legacy interface and some through the other
> interface. Currently, the legacy interface is not fully implemented and
> is only used for hotkeys and further debugging has to be done.
>
> The WMI interface takes a 64 bit integer, although uses 32 bits most of
> the time, and returns a 256-260 bytes buffer consists of either one ACPI
> buffer of 260 bytes, in the case of Matebook X (2017), or one ACPI
> package of two buffers, one with 4 bytes, and the other with 256 bytes.
> We only care about the latter 256 buffer in both cases since the 4 bytes
> always return zeros. The first byte of this 256 buffer always has the
> return status where 1 indicated error. Some models require calling the
> WMI interface twice to execute a command.
>
> # Add micmute LED support through WMI
>
> After implementing the WMI interface, micmute LED can be controlled
> easily. Models with the legacy interface fall back to ACPI EC method
> control since the legacy interface is not implemented.
>
> # Add battery charging protection support through WMI
>
> Most models, that has the WMI interface, are capable of battery
> protection where it can control battery charging thresholds and limits
> charging the battery to certain values.
>
> # Add fn-lock support through WMI
>
> The behavior of hotkeys is not the same among all models. Some models
> require fn-lock to do things like `Ctrl-Ins` or `Alt-PrtSc`. By default,
> hotkeys behave as special keys (media keys, Ins, etc), but if a modifier
> is used (ctrl, alt, shift) these keys behave as F1-F12 keys. If the Fn
> key is toggled on, the hotkeys with or without a modifier, behave as
> F1-F12 keys. This makes it impossible to use a modifier and `PrtSc` or
> `Ins`.
>
> Now, some models fix this by excluding `PrtSc` and `Ins` keys from being
> treated as F11 and F12 keys with the use of a modifier. However, some
> models do not, and fixes this by the so called fn-lock.
>
> Fn-lock inverts the behavior of the top row from special keys to F1-F12
> keys. So a modifier and a special key would be possible which make
> things like `Alt-Ins` possible. Now, with fn-lock we would have 4 modes:
>
> * Fn-key off & fn-lock off - hotkeys treated as special keys using a
>   modifier gives F1-F12 keys.
> * Fn-key on & fn-lock off - hotkeys treated as F1-F12 keys and using a
>   modifier gives F1-F12.
> * Fn-key off & fn-lock on - hotkeys are treated as F1-F12 keys and using
>   a modifier gives special keys.
> * Fn-key on & fn-lock on - hotkeys are treated as special keys and using
>   a modifier gives special keys.
>
> # Implement driver quirks and parameters
>
> The driver introduces 3 quirks and 2 parameters that can change the
> driver's behavior. These quirks being as:
> 1. Fixes reporting brightness keys twice since it's already handled by
>    acpi-video.
> 2. Some models need a short delay when setting battery thresholds to
>    prevent a race condition when two processes read/write.
> 3. Matebook X (2017) handles micmute led through the "legacy" interface
>    which is not currently implemented. Use ACPI EC method to control
>    this led.
>
> and the 2 parameters can enforce the behavior of quirk 1 & 2.
>
> # Add a debugfs interface to WMI
>
> An interface to the WMI management interface that allows easier
> debugging.
>

It doesn't apply to current for-next.

> Ayman Bagabas (9):
>   platform/x86: huawei-wmi: rename guid and driver name
>   platform/x86: huawei-wmi: move to platform driver
>   platform/x86: huawei-wmi: implement huawei wmi management interface
>   platform/x86: huawei-wmi: add quirks and module parameters
>   platform/x86: huawei-wmi: control micmute led through wmi interface
>   platform/x86: huawei-wmi: add battery charging thresholds
>   platform/x86: huawei-wmi: add fn-lock support
>   platform/x86: huawei-wmi: add sysfs interface support
>   platform/x86: huawei-wmi: add debugfs support
>
>  drivers/platform/x86/huawei-wmi.c | 710 ++++++++++++++++++++++++++----
>  1 file changed, 629 insertions(+), 81 deletions(-)
>
> --
> 2.20.1
>


-- 
With Best Regards,
Andy Shevchenko

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