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Subject: Re: [PATCH] platform/x86/intel: hid: Add DMI switches allow list
To:     =?UTF-8?Q?Barnab=c3=a1s_P=c5=91cze?= <pobrn@protonmail.com>,
        =?UTF-8?B?Sm9zw6kgRXhww7NzaXRv?= <jose.exposito89@gmail.com>
Cc:     alex.hung@canonical.com, mgross@linux.intel.com,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Tobias Gurtzick <magic@wizardtales.com>
References: <20210920160312.9787-1-jose.exposito89@gmail.com>
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From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <ca5834c0-3456-bda8-36d8-becd8e1a2590@redhat.com>
Date:   Tue, 21 Sep 2021 15:13:31 +0200
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Hi,

On 9/20/21 8:43 PM, Barnabás Pőcze wrote:
> Hi
> 
> 
> 2021. szeptember 20., hétfő 18:03 keltezéssel, José Expósito írta:
>> Some devices, even non convertible ones, can send incorrect
>> SW_TABLET_MODE reports.
>>
>> Add an allow list and accept such reports only from devices in it.
>>
>> Bug reported for Dell XPS 17 9710 on:
>> https://gitlab.freedesktop.org/libinput/libinput/-/issues/662
>>
>> Reported-by: Tobias Gurtzick <magic@wizardtales.com>
>> Suggested-by: Hans de Goede <hdegoede@redhat.com>
>> Tested-by: Tobias Gurtzick <magic@wizardtales.com>
>> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
>> ---
>>  drivers/platform/x86/intel/hid.c | 33 +++++++++++++++++++++++++++-----
>>  1 file changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/platform/x86/intel/hid.c b/drivers/platform/x86/intel/hid.c
>> index a33a5826e81a..24d26336e39a 100644
>> --- a/drivers/platform/x86/intel/hid.c
>> +++ b/drivers/platform/x86/intel/hid.c
>> @@ -118,6 +118,24 @@ static const struct dmi_system_id dmi_vgbs_allow_list[] = {
>>  	{ }
>>  };
>>
>> +/*
>> + * Some devices, even non convertible ones, can send incorrect SW_TABLET_MODE
>> + * reports. Accept such reports only from devices in this list.
>> + */
>> +static const struct dmi_system_id dmi_switches_auto_add_allow_list[] = {
>> +	{
>> +		.matches = {
>> +			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
>> +		},
>> +	},
>> +	{
>> +		.matches = {
>> +			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
>> +		},
>> +	},
>> +	{} /* Array terminator */
>> +};
>> +
>>  struct intel_hid_priv {
>>  	struct input_dev *input_dev;
>>  	struct input_dev *array;
>> @@ -455,11 +473,16 @@ static void notify_handler(acpi_handle handle, u32 event, void *context)
>>  	 *
>>  	 * See dual_accel_detect.h for more info on the dual_accel check.
>>  	 */
>> -	if (!priv->switches && !priv->dual_accel && (event == 0xcc || event == 0xcd)) {
>> -		dev_info(&device->dev, "switch event received, enable switches supports\n");
>> -		err = intel_hid_switches_setup(device);
>> -		if (err)
>> -			pr_err("Failed to setup Intel HID switches\n");
>> +	if (event == 0xcc || event == 0xcd) {
>> +		if (!dmi_check_system(dmi_switches_auto_add_allow_list))
>> +			return;
> 
> I think you should not check it every time. Maybe add a `bool` member
> to `struct intel_hid_priv`. Or maybe better: rename `dual_accel` to something like
> `autodetect_switch` and initialize it with `!dual_accel_detect() && dmi_check_system(...)`.

These events don't happen all that often. But this still is a good suggestion.

Since this is a regression fix of sorts I've gone ahead and made the suggested
changes myself (keeping José as author) and I've applied this to my tree,
see the version in the review-hans branch to see what the merged version
looks like.

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

I will also add this to the pdx86 fixes branch and include it in my
next pdx86-fixes for 5.15 pull-req to Linus.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> 
> 
>> +
>> +		if (!priv->switches && !priv->dual_accel) {
>> +			dev_info(&device->dev, "switch event received, enable switches supports\n");
>> +			err = intel_hid_switches_setup(device);
>> +			if (err)
>> +				pr_err("Failed to setup Intel HID switches\n");
>> +		}
>>  	}
>>
>>  	if (priv->wakeup_mode) {
>> --
>> 2.25.1
>>
>>
> 
> 
> Regards,
> Barnabás Pőcze
>