linux-kernel - Re: [PATCH v2 2/2] intel-hid: add alternative method to enable switches

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <u_tIRoW7nG4DQc7H_wcr9yn8oIc5rO9SsWKfOoJz4c9KKDJtUsYore_4tyNYxn3r0OpEOI5rsyrE__1Y2hbIc8lnS5cJKeeFmqyPdRjDVyU=@protonmail.com>
Date:   Thu, 03 Dec 2020 23:45:10 +0000
From:   Barnabás Pőcze <pobrn@...tonmail.com>
To:     Elia Devito <eliadevito@...il.com>
Cc:     Alex Hung <alex.hung@...onical.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] intel-hid: add alternative method to enable switches

Hi


2020. december 3., csütörtök 22:21 keltezéssel, Elia Devito írta:

> [...]
> diff --git a/drivers/platform/x86/intel-hid.c b/drivers/platform/x86/intel-hid.c
> index 86261970bd8f..fed24d4f28b8 100644
> --- a/drivers/platform/x86/intel-hid.c
> +++ b/drivers/platform/x86/intel-hid.c
> @@ -15,6 +15,9 @@
>  #include <linux/platform_device.h>
>  #include <linux/suspend.h>
>
> +/* When NOT in tablet mode, VGBS returns with the flag 0x40 */
> +#define TABLET_MODE_FLAG 0x40

I think `BIT(6)` would be better (linux/bits.h).


> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Alex Hung");
>
> @@ -89,9 +92,26 @@ static const struct dmi_system_id button_array_table[] = {
>  	{ }
>  };
> [...]
> +static void detect_tablet_mode(struct platform_device *device)

I believe `report_tablet_mode_state()` or something similar would be a more apt name.


> +{
> +	struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
> +	acpi_handle handle = ACPI_HANDLE(&device->dev);
> +	unsigned long long vgbs;
> +	int m;
> +
> +	if (!intel_hid_evaluate_method(handle, INTEL_HID_DSM_VGBS_FN, &vgbs))
> +		return;
> +
> +	m = !(vgbs & TABLET_MODE_FLAG);
> +	input_report_switch(priv->switches, SW_TABLET_MODE, m);
> +	input_sync(priv->switches);
> +}
> +
>  static void notify_handler(acpi_handle handle, u32 event, void *context)
>  {
>  	struct platform_device *device = context;
> @@ -363,6 +415,13 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
>  		if (event == 0xce)
>  			goto wakeup;
>
> +		/*
> +		 * Switch events will wake the device and report the new switch
> +		 * position to the input subsystem.
> +		 */
> +		if (priv->switches && (event == 0xcc || event == 0xcd))
> +			goto wakeup;
> +
>  		/* Wake up on 5-button array events only. */
>  		if (event == 0xc0 || !priv->array)
>  			return;
> @@ -374,6 +433,21 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
>
>  wakeup:
>  		pm_wakeup_hard_event(&device->dev);
> +
> +		if (priv->switches) {
> +			if (event == 0xcc) {
> +				input_report_switch(priv->switches, SW_TABLET_MODE, 1);
> +				input_sync(priv->switches);
> +				return;
> +			}
> +
> +			if (event == 0xcd) {
> +				input_report_switch(priv->switches, SW_TABLET_MODE, 0);
> +				input_sync(priv->switches);
> +				return;
> +			}
> +		}
> +
>  		return;
>  	}
>
> @@ -398,6 +472,20 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
>  		}
>  	}
>
> +	if (priv->switches) {
> +		if (event == 0xcc) {
> +			input_report_switch(priv->switches, SW_TABLET_MODE, 1);
> +			input_sync(priv->switches);
> +			return;
> +		}
> +
> +		if (event == 0xcd) {
> +			input_report_switch(priv->switches, SW_TABLET_MODE, 0);
> +			input_sync(priv->switches);
> +			return;
> +		}
> +	}

Wouldn't be better to create a new function `bool report_tablet_mode_event()`
which would basically contain the above `if` or better, a `switch`, and then
you could use it here and in the wake-up path like the following:

```
if (report_tablet_mode_event(priv->switches, event))
  return;
```
(or similarly)


> +
>  	/* 0xC0 is for HID events, other values are for 5 button array */
>  	if (event != 0xc0) {
>  		if (!priv->array ||
> @@ -485,6 +573,16 @@ static int intel_hid_probe(struct platform_device *device)
>  			pr_err("Failed to setup Intel 5 button array hotkeys\n");
>  	}
>
> +	/* Setup switches for devices that we know VGBS return correctly */
> +	if (dmi_check_system(dmi_vgbs_allow_list)) {
> +		dev_info(&device->dev, "platform supports switches\n");
> +		err = intel_hid_switches_setup(device);
> +		if (err)
> +			pr_err("Failed to setup Intel HID switches\n");
> +		else
> +			detect_tablet_mode(device);
> +	}
> +
>  	status = acpi_install_notify_handler(handle,
>  					     ACPI_DEVICE_NOTIFY,
>  					     notify_handler,
> --
> 2.28.0


Regards,
Barnabás Pőcze