[PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[Hans de Goede]

asus-nb-wmi does not add any extra functionality on these Asus
Transformer books. They have detachable keyboards, so the hotkeys are
send through a HID device (and handled by the hid-asus driver) and also
the rfkill functionality is not used on these devices.

Besides not adding any extra functionality, initializing the WMI interface
on these devices actually has a negative side-effect. For some reason
the \_SB.ATKD.INIT() function which asus_wmi_platform_init() calls drives
GPO2 (INT33FC:02) pin 8, which is connected to the front facing webcam LED,
high and there is no (WMI or other) interface to drive this low again
causing the LED to be permanently on, even during suspend.

This commit adds a blacklist of DMI system_ids on which not to load the
asus-nb-wmi and adds these Transformer books to this list. This fixes
the webcam LED being permanently on under Linux.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/platform/x86/asus-nb-wmi.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/platform/x86/asus-nb-wmi.c b/drivers/platform/x86/asus-nb-wmi.c
index 6f12747a359a..c4404d9c1de4 100644
--- a/drivers/platform/x86/asus-nb-wmi.c
+++ b/drivers/platform/x86/asus-nb-wmi.c
@@ -515,9 +515,33 @@ static struct asus_wmi_driver asus_nb_wmi_driver = {
 	.detect_quirks = asus_nb_wmi_quirks,
 };
 
+static const struct dmi_system_id asus_nb_wmi_blacklist[] __initconst = {
+	{
+		/*
+		 * asus-nb-wm adds no functionality. The T100TA has a detachable
+		 * USB kbd, so no hotkeys and it has no WMI rfkill; and loading
+		 * asus-nb-wm causes the camera LED to turn and _stay_ on.
+		 */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T100TA"),
+		},
+	},
+	{
+		/* The Asus T200TA has the same issue as the T100TA */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T200TA"),
+		},
+	},
+	{} /* Terminating entry */
+};
 
 static int __init asus_nb_wmi_init(void)
 {
+	if (dmi_check_system(asus_nb_wmi_blacklist))
+		return -ENODEV;
+
 	return asus_wmi_register_driver(&asus_nb_wmi_driver);
 }
 
-- 
2.26.0

Re: [PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[Hans de Goede]

Hi,

On 4/23/20 12:05 AM, Hans de Goede wrote:
> asus-nb-wmi does not add any extra functionality on these Asus
> Transformer books. They have detachable keyboards, so the hotkeys are
> send through a HID device (and handled by the hid-asus driver) and also
> the rfkill functionality is not used on these devices.
> 
> Besides not adding any extra functionality, initializing the WMI interface
> on these devices actually has a negative side-effect. For some reason
> the \_SB.ATKD.INIT() function which asus_wmi_platform_init() calls drives
> GPO2 (INT33FC:02) pin 8, which is connected to the front facing webcam LED,
> high and there is no (WMI or other) interface to drive this low again
> causing the LED to be permanently on, even during suspend.
> 
> This commit adds a blacklist of DMI system_ids on which not to load the
> asus-nb-wmi and adds these Transformer books to this list. This fixes
> the webcam LED being permanently on under Linux.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Because of the BYT/CHT work which I do as a side project I have a bunch
of BYT/CHT based 2-in-1s as test devices, including the T100TA and T200TA.

So recently I've been looking into properly reporting SW_TABLET_MODE
state to userspace to let userspace know if the keyboard of these
detachables is attached or not; and guess what, the Asus models
report this through WMI. So blacklisting is not the right thing to do
here after all :|  I do have a plan for another fix for this
(which will also involve DMI matching)...

Andy, Darren, I see that you have already added this to the for-next
branch of linux-platform-drivers-x86. I'm not sure what your vision
on forced pushed there is. If forced pushes are ok, please drop this
patch. If not let me know and I will send out a revert.

Regards,

Hans



> ---
>   drivers/platform/x86/asus-nb-wmi.c | 24 ++++++++++++++++++++++++
>   1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/platform/x86/asus-nb-wmi.c b/drivers/platform/x86/asus-nb-wmi.c
> index 6f12747a359a..c4404d9c1de4 100644
> --- a/drivers/platform/x86/asus-nb-wmi.c
> +++ b/drivers/platform/x86/asus-nb-wmi.c
> @@ -515,9 +515,33 @@ static struct asus_wmi_driver asus_nb_wmi_driver = {
>   	.detect_quirks = asus_nb_wmi_quirks,
>   };
>   
> +static const struct dmi_system_id asus_nb_wmi_blacklist[] __initconst = {
> +	{
> +		/*
> +		 * asus-nb-wm adds no functionality. The T100TA has a detachable
> +		 * USB kbd, so no hotkeys and it has no WMI rfkill; and loading
> +		 * asus-nb-wm causes the camera LED to turn and _stay_ on.
> +		 */
> +		.matches = {
> +			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
> +			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T100TA"),
> +		},
> +	},
> +	{
> +		/* The Asus T200TA has the same issue as the T100TA */
> +		.matches = {
> +			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
> +			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T200TA"),
> +		},
> +	},
> +	{} /* Terminating entry */
> +};
>   
>   static int __init asus_nb_wmi_init(void)
>   {
> +	if (dmi_check_system(asus_nb_wmi_blacklist))
> +		return -ENODEV;
> +
>   	return asus_wmi_register_driver(&asus_nb_wmi_driver);
>   }
>   
> 

Re: [PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[Andy Shevchenko]

On Fri, May 8, 2020 at 10:54 PM Hans de Goede <hdegoede@redhat.com> wrote:
> On 4/23/20 12:05 AM, Hans de Goede wrote:

> Andy, Darren, I see that you have already added this to the for-next
> branch of linux-platform-drivers-x86. I'm not sure what your vision
> on forced pushed there is. If forced pushes are ok, please drop this
> patch. If not let me know and I will send out a revert.

Forced pushes are not okay, but we have exceptions in some cases.
It would be done here, but there are complications, i.e. we have
already immutable branch merged from MFD. Of course, I would remerge
it again, but I think we better not to do this right now, so, revert
seems a less painful in this case. Or, if you have already done
something better, than keep it as follow up improvement rather than
pure revert.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[Andy Shevchenko]

On Fri, May 8, 2020 at 11:56 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Fri, May 8, 2020 at 10:54 PM Hans de Goede <hdegoede@redhat.com> wrote:
> > On 4/23/20 12:05 AM, Hans de Goede wrote:
>
> > Andy, Darren, I see that you have already added this to the for-next
> > branch of linux-platform-drivers-x86. I'm not sure what your vision
> > on forced pushed there is. If forced pushes are ok, please drop this
> > patch. If not let me know and I will send out a revert.
>
> Forced pushes are not okay, but we have exceptions in some cases.
> It would be done here, but there are complications, i.e. we have
> already immutable branch merged from MFD. Of course, I would remerge
> it again, but I think we better not to do this right now, so, revert
> seems a less painful in this case. Or, if you have already done
> something better, than keep it as follow up improvement rather than
> pure revert.

Oops, it seems I was quick enough to push this to v5.7-rc4. So, please
send revert!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] platform/x86: asus-nb-wmi: Do not load on Asus T100TA and T200TA

[Hans de Goede]

Hi,

On 5/9/20 2:23 PM, Andy Shevchenko wrote:
> On Fri, May 8, 2020 at 11:56 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
>>
>> On Fri, May 8, 2020 at 10:54 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>> On 4/23/20 12:05 AM, Hans de Goede wrote:
>>
>>> Andy, Darren, I see that you have already added this to the for-next
>>> branch of linux-platform-drivers-x86. I'm not sure what your vision
>>> on forced pushed there is. If forced pushes are ok, please drop this
>>> patch. If not let me know and I will send out a revert.
>>
>> Forced pushes are not okay, but we have exceptions in some cases.
>> It would be done here, but there are complications, i.e. we have
>> already immutable branch merged from MFD. Of course, I would remerge
>> it again, but I think we better not to do this right now, so, revert
>> seems a less painful in this case. Or, if you have already done
>> something better, than keep it as follow up improvement rather than
>> pure revert.

Ok, doing the revert is fine with me, I've prepped it and I will
send it out right away.

> Oops, it seems I was quick enough to push this to v5.7-rc4. So, please
> send revert!

Note the commit does not break anything; it even works as advertised
to fix the camera LED being stuck in on state at boot on the Asus T100TA
and Asus T200TA.

The problem is that I'm working on making various 2-in-1s report their
tablet-mode state (SW_TABLET_MODE) to userspace; and I've found that
these 2 Asus models (and other Asus models) report this through WMI.

So the blacklisting of these 2 models inside asus-nb-wmi needs to be
dropped to make the SW_TABLET_MODE reporting work once I have added that
to the asus-nb-wmi driver, so the revert is to prepare for that it
does not fix any regression, since the current version of asus-nb-wmi
does not handle SW_TABLET_MODE.

So there is no need to rush the revert upstream, it can go to 5.8 together
with the asus-nb-wmi changes to add SW_TABLET_MODE support.

The reason I was asking to drop the commit was because I came to the
conclusion that in the end the blacklist is not what we want. But for
now having the blacklist is fine.

Regards,

Hans