Re: [PATCH] HID: ite: Only bind to keyboard USB interface on Acer SW5-012 keyboard dock

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

On Fri, Jan 31, 2020 at 6:17 PM Z R <zdenda.rampas@gmail.com> wrote:
>
> Hi Benjamin,
> in last log touchpad.log (omg, should be keyboard.log), I pressed fn-f3 multiple times. I got one two liner:
>
> # ReportID: 3 / Wireless Radio Button: 0 | #
> E: 000007.606583 2 03 00

great, thanks.

>
> every time i release f3. Does not matter what is happening with fn-key. (could be released already or still pushed down). This log was collected with last patch from Hans applied.

Actually, it doesn't really matter if the patch from Hans was applied
or not. I am looking at the raw event from the device before kernel
processing :)

May I ask you one more thing: can you run `libinput record` (as root)
on the touchpad? I need to know how many fingers the touchpad is
capable to detect, as right now, my tests are failing because of that.

>
> Sorry for the mess I caused :-) I still don't get how you guys manage to have your emails so well polished and readable.

No worries. Having a responsive user is much more valuable than
someone who takes ages to reply even in a clear and well polished
message :)

Cheers,
Benjamin

>
> Bye
> Zdeněk
>
> pá 31. 1. 2020 v 18:00 odesílatel Benjamin Tissoires <benjamin.tissoires@redhat.com> napsal:
>>
>> On Fri, Jan 31, 2020 at 5:09 PM Z R <zdenda.rampas@gmail.com> wrote:
>> >
>> > I believe I pressed wifi button on both replays for keyboard.
>>
>> Yep, I can see that. Just to double check, on the last log, you
>> pressed the wifi button twice?
>>
>> Anyway, thanks for all the logs, I should have enough to implement the
>> regression tests.
>>
>> Cheers,
>> Benjamin
>>
>> >
>> > With latest patch from Hans on top of v5.5.0 touchpads "two finger scrolling" is working again. Attaching current hid-record for keyboard with Wifi button pressed. Events in log appeared after f3 button was "released".
>> >
>> > Thanks
>> >
>> > Zdeněk
>> >
>> > pá 31. 1. 2020 v 16:45 odesílatel Hans de Goede <hdegoede@redhat.com> napsal:
>> >>
>> >> Hi,
>> >>
>> >> On 1/31/20 4:38 PM, Z R wrote:
>> >> > Hi Benjamin,
>> >> > hid-record for keyboard and touchpad. With Commit 8f18eca9ebc5 reverted and from unmodified kernel.
>> >> >
>> >> > I hope it is what you asked for :-)
>> >> >
>> >> > Currently waiting for reworked patch from Hans.
>> >>
>> >> I just send you the reworked patch.
>> >>
>> >> Does the recordning include pressing of the wlan on/off key (Fn + F3 I believe) ?
>> >> That is the whole reason why the special hid-ite driver is necessary.
>> >>
>> >> Benjamin about the wlan on/off key. AFAICR on a press + release of the key a
>> >> single hid input report for the generic-desktop  Wireless Radio Controls group
>> >> is send. This input-report only has the one button with usage code HID_GD_RFKILL_BTN
>> >> in there and it is always 0. It is as if the input-report is only send on release
>> >> and not on press. So the hid-ite code emulates a press + release whenever the
>> >> input-report is send.
>> >>
>> >> IOW the receiving of the input report is (ab)used as indication of the button
>> >> having been pressed.
>> >>
>> >> Regards,
>> >>
>> >> Hans
>> >>
>> >>
>> >> >
>> >> > Bye for now
>> >> > Zdeněk
>> >> >
>> >> > pá 31. 1. 2020 v 15:12 odesílatel Benjamin Tissoires <benjamin.tissoires@redhat.com <mailto:benjamin.tissoires@redhat.com>> napsal:
>> >> >
>> >> >     On Fri, Jan 31, 2020 at 3:04 PM Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>> wrote:
>> >> >      >
>> >> >      > Hi,
>> >> >      >
>> >> >      > On 1/31/20 2:54 PM, Benjamin Tissoires wrote:
>> >> >      > > On Fri, Jan 31, 2020 at 2:41 PM Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>> wrote:
>> >> >      > >>
>> >> >      > >> Hi,
>> >> >      > >>
>> >> >      > >> On 1/31/20 2:10 PM, Benjamin Tissoires wrote:
>> >> >      > >>> Hi Hans,
>> >> >      > >>>
>> >> >      > >>> On Fri, Jan 31, 2020 at 1:46 PM Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>> wrote:
>> >> >      > >>>>
>> >> >      > >>>> Commit 8f18eca9ebc5 ("HID: ite: Add USB id match for Acer SW5-012 keyboard
>> >> >      > >>>> dock") added the USB id for the Acer SW5-012's keyboard dock to the
>> >> >      > >>>> hid-ite driver to fix the rfkill driver not working.
>> >> >      > >>>>
>> >> >      > >>>> Most keyboard docks with an ITE 8595 keyboard/touchpad controller have the
>> >> >      > >>>> "Wireless Radio Control" bits which need the special hid-ite driver on the
>> >> >      > >>>> second USB interface (the mouse interface) and their touchpad only supports
>> >> >      > >>>> mouse emulation, so using generic hid-input handling for anything but
>> >> >      > >>>> the "Wireless Radio Control" bits is fine. On these devices we simply bind
>> >> >      > >>>> to all USB interfaces.
>> >> >      > >>>>
>> >> >      > >>>> But unlike other ITE8595 using keyboard docks, the Acer Aspire Switch 10
>> >> >      > >>>> (SW5-012)'s touchpad not only does mouse emulation it also supports
>> >> >      > >>>> HID-multitouch and all the keys including the "Wireless Radio Control"
>> >> >      > >>>> bits have been moved to the first USB interface (the keyboard intf).
>> >> >      > >>>>
>> >> >      > >>>> So we need hid-ite to handle the first (keyboard) USB interface and have
>> >> >      > >>>> it NOT bind to the second (mouse) USB interface so that that can be
>> >> >      > >>>> handled by hid-multitouch.c and we get proper multi-touch support.
>> >> >      > >>>>
>> >> >      > >>>> This commit adds a match callback to hid-ite which makes it only
>> >> >      > >>>> match the first USB interface when running on the Acer SW5-012,
>> >> >      > >>>> fixing the regression to mouse-emulation mode introduced by adding the
>> >> >      > >>>> keyboard dock USB id.
>> >> >      > >>>>
>> >> >      > >>>> Note the match function only does the special only bind to the first
>> >> >      > >>>> USB interface on the Acer SW5-012, on other devices the hid-ite driver
>> >> >      > >>>> actually must bind to the second interface as that is where the
>> >> >      > >>>> "Wireless Radio Control" bits are.
>> >> >      > >>>
>> >> >      > >>> This is not a full review, but a couple of things that popped out
>> >> >      > >>> while scrolling through the patch.
>> >> >      > >>>
>> >> >      > >>>>
>> >> >      > >>>> Cc: stable@vger.kernel.org <mailto:stable@vger.kernel.org>
>> >> >      > >>>> Fixes: 8f18eca9ebc5 ("HID: ite: Add USB id match for Acer SW5-012 keyboard dock")
>> >> >      > >>>> Reported-by: Zdeněk Rampas <zdenda.rampas@gmail.com <mailto:zdenda.rampas@gmail.com>>
>> >> >      > >>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>>
>> >> >      > >>>> ---
>> >> >      > >>>>    drivers/hid/hid-ite.c | 34 ++++++++++++++++++++++++++++++++++
>> >> >      > >>>>    1 file changed, 34 insertions(+)
>> >> >      > >>>>
>> >> >      > >>>> diff --git a/drivers/hid/hid-ite.c b/drivers/hid/hid-ite.c
>> >> >      > >>>> index c436e12feb23..69a4ddfd033d 100644
>> >> >      > >>>> --- a/drivers/hid/hid-ite.c
>> >> >      > >>>> +++ b/drivers/hid/hid-ite.c
>> >> >      > >>>> @@ -8,9 +8,12 @@
>> >> >      > >>>>    #include <linux/input.h>
>> >> >      > >>>>    #include <linux/hid.h>
>> >> >      > >>>>    #include <linux/module.h>
>> >> >      > >>>> +#include <linux/usb.h>
>> >> >      > >>>>
>> >> >      > >>>>    #include "hid-ids.h"
>> >> >      > >>>>
>> >> >      > >>>> +#define ITE8595_KBD_USB_INTF           0
>> >> >      > >>>> +
>> >> >      > >>>>    static int ite_event(struct hid_device *hdev, struct hid_field *field,
>> >> >      > >>>>                        struct hid_usage *usage, __s32 value)
>> >> >      > >>>>    {
>> >> >      > >>>> @@ -37,6 +40,36 @@ static int ite_event(struct hid_device *hdev, struct hid_field *field,
>> >> >      > >>>>           return 0;
>> >> >      > >>>>    }
>> >> >      > >>>>
>> >> >      > >>>> +static bool ite_match(struct hid_device *hdev, bool ignore_special_driver)
>> >> >      > >>>> +{
>> >> >      > >>>> +       struct usb_interface *intf;
>> >> >      > >>>> +
>> >> >      > >>>> +       if (ignore_special_driver)
>> >> >      > >>>> +               return false;
>> >> >      > >>>> +
>> >> >      > >>>> +       /*
>> >> >      > >>>> +        * Most keyboard docks with an ITE 8595 keyboard/touchpad controller
>> >> >      > >>>> +        * have the "Wireless Radio Control" bits which need this special
>> >> >      > >>>> +        * driver on the second USB interface (the mouse interface). On
>> >> >      > >>>> +        * these devices we simply bind to all USB interfaces.
>> >> >      > >>>> +        *
>> >> >      > >>>> +        * The Acer Aspire Switch 10 (SW5-012) is special, its touchpad
>> >> >      > >>>> +        * not only does mouse emulation it also supports HID-multitouch
>> >> >      > >>>> +        * and all the keys including the "Wireless Radio Control" bits
>> >> >      > >>>> +        * have been moved to the first USB interface (the keyboard intf).
>> >> >      > >>>> +        *
>> >> >      > >>>> +        * We want the hid-multitouch driver to bind to the touchpad, so on
>> >> >      > >>>> +        * the Acer SW5-012 we should only bind to the keyboard USB intf.
>> >> >      > >>>> +        */
>> >> >      > >>>> +       if (hdev->bus != BUS_USB || hdev->vendor != USB_VENDOR_ID_SYNAPTICS ||
>> >> >      > >>>> +                    hdev->product != USB_DEVICE_ID_SYNAPTICS_ACER_SWITCH5_012)
>> >> >      > >>>
>> >> >      > >>> Isn't there an existing matching function we can use here, instead of
>> >> >      > >>> checking each individual field?
>> >> >      > >>
>> >> >      > >> There is hid_match_one_id() but that is not exported (can be fixed) and it
>> >> >      > >> requires a struct hid_device_id, which either requires declaring an extra
>> >> >      > >> standalone struct hid_device_id for the SW5-012 kbd-dock, or hardcoding an
>> >> >      > >> index into the existing hid_device_id array for the driver (with the hardcoding
>> >> >      > >> being error prone, so not a good idea).
>> >> >      > >>
>> >> >      > >> Given the problems with using hid_match_one_id() I decided to just go with
>> >> >      > >> the above.
>> >> >      > >
>> >> >      > > right. An other solution would be to have a local macro/function that
>> >> >      > > does that. Because as soon as you start adding a quirk, an other comes
>> >> >      > > right after.
>> >> >      > >
>> >> >      > >>
>> >> >      > >> But see below.
>> >> >      > >>
>> >> >      > >>>
>> >> >      > >>>> +               return true;
>> >> >      > >>>> +
>> >> >      > >>>> +       intf = to_usb_interface(hdev->dev.parent);
>> >> >      > >>>
>> >> >      > >>> And this is oops-prone. You need:
>> >> >      > >>> - ensure hid_is_using_ll_driver(hdev, &usb_hid_driver) returns true.
>> >> >      > >>> - add a dependency on USBHID in the KConfig now that you are checking
>> >> >      > >>> on the USB transport layer.
>> >> >      > >>>
>> >> >      > >>> That being said, I would love instead:
>> >> >      > >>> - to have a non USB version of this match, where you decide which
>> >> >      > >>> component needs to be handled based on the report descriptor
>> >> >      > >>
>> >> >      > >> Actually your idea to use the desciptors is not bad, but since what
>> >> >      > >> we really want is to not bind to the interface which is marked for the
>> >> >      > >> hid-multitouch driver I just realized we can just check that.
>> >> >      > >>
>> >> >      > >> So how about:
>> >> >      > >>
>> >> >      > >> static bool ite_match(struct hid_device *hdev, bool ignore_special_driver)
>> >> >      > >> {
>> >> >      > >>           if (ignore_special_driver)
>> >> >      > >>                   return false;
>> >> >      > >>
>> >> >      > >>           /*
>> >> >      > >>            * Some keyboard docks with an ITE 8595 keyboard/touchpad controller
>> >> >      > >>            * support the HID multitouch protocol for the touchpad, in that
>> >> >      > >>            * case the "Wireless Radio Control" bits which we care about are
>> >> >      > >>            * on the other interface; and we should not bind to the multitouch
>> >> >      > >>            * capable interface as that breaks multitouch support.
>> >> >      > >>            */
>> >> >      > >>           return hdev->group != HID_GROUP_MULTITOUCH_WIN_8;
>> >> >      > >> }
>> >> >      > >
>> >> >      > > Yep, I like that very much :)
>> >> >      >
>> >> >      > Actually if we want to check the group and there are only 2 interfaces we do
>> >> >      > not need to use the match callback at all, w e can simply match on the
>> >> >      > group of the interface which we do want:
>> >> >      >
>> >> >      > diff --git a/drivers/hid/hid-ite.c b/drivers/hid/hid-ite.c
>> >> >      > index db0f35be5a8b..21bd48f16033 100644
>> >> >      > --- a/drivers/hid/hid-ite.c
>> >> >      > +++ b/drivers/hid/hid-ite.c
>> >> >      > @@ -56,8 +56,9 @@ static const struct hid_device_id ite_devices[] = {
>> >> >      >         { HID_USB_DEVICE(USB_VENDOR_ID_ITE, USB_DEVICE_ID_ITE8595) },
>> >> >      >         { HID_USB_DEVICE(USB_VENDOR_ID_258A, USB_DEVICE_ID_258A_6A88) },
>> >> >      >         /* ITE8595 USB kbd ctlr, with Synaptics touchpad connected to it. */
>> >> >      > -       { HID_USB_DEVICE(USB_VENDOR_ID_SYNAPTICS,
>> >> >      > -                        USB_DEVICE_ID_SYNAPTICS_ACER_SWITCH5_012) },
>> >> >      > +       { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
>> >> >      > +                    USB_VENDOR_ID_SYNAPTICS,
>> >> >      > +                    USB_DEVICE_ID_SYNAPTICS_ACER_SWITCH5_012) },
>> >> >      >         { }
>> >> >      >   };
>> >> >      >   MODULE_DEVICE_TABLE(hid, ite_devices);
>> >> >      >
>> >> >      > Much cleaner
>> >> >
>> >> >     yep
>> >> >
>> >> >      > (and now I don't need to write a test, which is always
>> >> >      > a good motivation to come up with a cleaner solution :)
>> >> >
>> >> >     Hehe, too bad, you already picked up my curiosity on this one, and I
>> >> >     really would like to see the report descriptors and some events of the
>> >> >     keys that are fixed by hid-ite.c.
>> >> >     <with a low voice>This will be a hard requirement to accept this patch </joke>.
>> >> >
>> >> >     More seriously, Zdeněk, can you run hid-recorder from
>> >> >     https://gitlab.freedesktop.org/libevdev/hid-tools/ and provide me the
>> >> >     report descriptor for all of your ITE HID devices? I'll add the
>> >> >     matching tests in hid-tools and be sure we do not regress in the
>> >> >     future.
>> >> >
>> >> >      >
>> >> >      > Let me turn this into a proper patch and then I will send that to
>> >> >      > Zdeněk (off-list) for him to test (note don't worry if you do
>> >> >      > not have time to test this weekend, then I'll do it on Monday).
>> >> >      >
>> >> >      > Regards,
>> >> >      >
>> >> >      > Hans
>> >> >      >
>> >> >      > p.s.
>> >> >      >
>> >> >      > 1. My train is approaching Brussels (Fosdem) so my email response
>> >> >      > time will soon become irregular.
>> >> >
>> >> >     How dare you? :)
>> >> >
>> >> >      >
>> >> >      > 2. Benjamin will you be at Fosdem too ?
>> >> >      >
>> >> >
>> >> >     Unfortunately no. Already got my quota of meeting people for this year
>> >> >     between Kernel Recipes in September, XDC in October and LCA last week.
>> >> >     So I need to keep in a quiet environment for a little bit :)
>> >> >
>> >> >     Cheers,
>> >> >     Benjamin
>> >> >
>> >>
>>