Message-ID: <20190725200509.snft3xy65ngaaxvs@960>
Date:   Thu, 25 Jul 2019 16:08:15 -0400
From:   Ayman Bagabas <ayman.bagabas@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...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 19/07/25 08:33PM, Andy Shevchenko wrote:
> 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.

Hey Andi,

I was basing them on the stable branch.

It doesn't apply because of commit 440c4983de262f78033ec58f6abcd199a664327d
(platform/x86: wmi: add context argument to the probe function)

One line change in huawei-wmi.c:
-static int huawei_wmi_probe(struct wmi_device *wdev)
+static int huawei_wmi_probe(struct wmi_device *wdev, const void *context)

I'll address that in the next version. For now, feedback is really
appreciated.

> 
> > 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

-- 
Thank you,
Ayman

Powered by blists - more mailing lists