2019-11-06 11:04:30

by Blaž Hrastnik

Subject: [PATCH] HID: Improve Windows Precision Touchpad detection.

Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing
data used to verify the touchpad as a Windows Precision Touchpad.

0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
0x09, 0xC5, // USAGE (Vendor Usage 0xC5)
0x15, 0x00, // LOGICAL_MINIMUM (0)
0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
0x75, 0x08, // REPORT_SIZE (8)
0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256))
0xb1, 0x02, // FEATURE (Data,Var,Abs)

However, some devices, namely Microsoft's Surface line of products
instead implement a "segmented device certification report" (usage 0xC6)
which returns the same report, but in smaller chunks.

0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined)
0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
0x09, 0xC6, // USAGE (Vendor usage for segment #)
0x25, 0x08, // LOGICAL_MAXIMUM (8)
0x75, 0x08, // REPORT_SIZE (8)
0x95, 0x01, // REPORT_COUNT (1)
0xb1, 0x02, // FEATURE (Data,Var,Abs)
0x09, 0xC7, // USAGE (Vendor Usage)
0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
0x95, 0x20, // REPORT_COUNT (32)
0xb1, 0x02, // FEATURE (Data,Var,Abs)

By expanding Win8 touchpad detection to also look for the segmented
report, all Surface touchpads are now properly recognized by
hid-multitouch.

Signed-off-by: Blaž Hrastnik <[email protected]>
---
drivers/hid/hid-core.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 63fdbf09b044..2af597cd5d65 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -742,6 +742,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
parser->global.report_size == 8)
parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
+
+ if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
+ parser->global.report_size == 8)
+ parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
}

static void hid_scan_collection(struct hid_parser *parser, unsigned type)
--
2.23.0

2019-11-07 08:51:32

by Benjamin Tissoires

Subject: Re: [PATCH] HID: Improve Windows Precision Touchpad detection.

Hi Blaž,

On Wed, Nov 6, 2019 at 12:03 PM Blaž Hrastnik <[email protected]> wrote:
>
> Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing
> data used to verify the touchpad as a Windows Precision Touchpad.
>
> 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> 0x09, 0xC5, // USAGE (Vendor Usage 0xC5)
> 0x15, 0x00, // LOGICAL_MINIMUM (0)
> 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> 0x75, 0x08, // REPORT_SIZE (8)
> 0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256))
> 0xb1, 0x02, // FEATURE (Data,Var,Abs)
>
> However, some devices, namely Microsoft's Surface line of products
> instead implement a "segmented device certification report" (usage 0xC6)
> which returns the same report, but in smaller chunks.
>
> 0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined)
> 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> 0x09, 0xC6, // USAGE (Vendor usage for segment #)
> 0x25, 0x08, // LOGICAL_MAXIMUM (8)
> 0x75, 0x08, // REPORT_SIZE (8)
> 0x95, 0x01, // REPORT_COUNT (1)
> 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> 0x09, 0xC7, // USAGE (Vendor Usage)
> 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> 0x95, 0x20, // REPORT_COUNT (32)
> 0xb1, 0x02, // FEATURE (Data,Var,Abs)
>
> By expanding Win8 touchpad detection to also look for the segmented
> report, all Surface touchpads are now properly recognized by
> hid-multitouch.
>
> Signed-off-by: Blaž Hrastnik <[email protected]>
> ---

This looks good to me.
We *could* shorten the ifs and make only one conditional, but I find
it this way more readable and future proof.

There is just one last step required before we merge this: add a
regression test so we ensure we do not break it in the future.

It should be merely a matter of sending a MR to
https://gitlab.freedesktop.org/libevdev/hid-tools.
It should consist in adding the report descriptor in the same way we
have https://gitlab.freedesktop.org/libevdev/hid-tools/blob/master/tests/test_multitouch.py#L1656-1658.
Then, make sure an unpatched kernel breaks the multitouch test (sudo
pytest-3 -k 'multitouch and TestPTP') and that a patched kernel is
fixed.

Cheers,
Benjamin

> drivers/hid/hid-core.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 63fdbf09b044..2af597cd5d65 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -742,6 +742,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
> if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
> parser->global.report_size == 8)
> parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> +
> + if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
> + parser->global.report_size == 8)
> + parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> }
>
> static void hid_scan_collection(struct hid_parser *parser, unsigned type)
> --
> 2.23.0
>

2019-11-07 09:11:29

by Blaž Hrastnik

Subject: Re: [PATCH] HID: Improve Windows Precision Touchpad detection.

I've submitted a test containing the Surface Book 2 descriptor.

https://gitlab.freedesktop.org/libevdev/hid-tools/merge_requests/59

Blaž

On Thu, 7 Nov 2019, at 17:48, Benjamin Tissoires wrote:
> Hi Blaž,
>
> On Wed, Nov 6, 2019 at 12:03 PM Blaž Hrastnik <[email protected]> wrote:
> >
> > Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing
> > data used to verify the touchpad as a Windows Precision Touchpad.
> >
> > 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> > 0x09, 0xC5, // USAGE (Vendor Usage 0xC5)
> > 0x15, 0x00, // LOGICAL_MINIMUM (0)
> > 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> > 0x75, 0x08, // REPORT_SIZE (8)
> > 0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256))
> > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> >
> > However, some devices, namely Microsoft's Surface line of products
> > instead implement a "segmented device certification report" (usage 0xC6)
> > which returns the same report, but in smaller chunks.
> >
> > 0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined)
> > 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> > 0x09, 0xC6, // USAGE (Vendor usage for segment #)
> > 0x25, 0x08, // LOGICAL_MAXIMUM (8)
> > 0x75, 0x08, // REPORT_SIZE (8)
> > 0x95, 0x01, // REPORT_COUNT (1)
> > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> > 0x09, 0xC7, // USAGE (Vendor Usage)
> > 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> > 0x95, 0x20, // REPORT_COUNT (32)
> > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> >
> > By expanding Win8 touchpad detection to also look for the segmented
> > report, all Surface touchpads are now properly recognized by
> > hid-multitouch.
> >
> > Signed-off-by: Blaž Hrastnik <[email protected]>
> > ---
>
> This looks good to me.
> We *could* shorten the ifs and make only one conditional, but I find
> it this way more readable and future proof.
>
> There is just one last step required before we merge this: add a
> regression test so we ensure we do not break it in the future.
>
> It should be merely a matter of sending a MR to
> https://gitlab.freedesktop.org/libevdev/hid-tools.
> It should consist in adding the report descriptor in the same way we
> have
> https://gitlab.freedesktop.org/libevdev/hid-tools/blob/master/tests/test_multitouch.py#L1656-1658.
> Then, make sure an unpatched kernel breaks the multitouch test (sudo
> pytest-3 -k 'multitouch and TestPTP') and that a patched kernel is
> fixed.
>
> Cheers,
> Benjamin
>
> > drivers/hid/hid-core.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > index 63fdbf09b044..2af597cd5d65 100644
> > --- a/drivers/hid/hid-core.c
> > +++ b/drivers/hid/hid-core.c
> > @@ -742,6 +742,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
> > if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
> > parser->global.report_size == 8)
> > parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> > +
> > + if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
> > + parser->global.report_size == 8)
> > + parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> > }
> >
> > static void hid_scan_collection(struct hid_parser *parser, unsigned type)
> > --
> > 2.23.0
> >
>
>

2019-11-18 10:06:28

by Benjamin Tissoires

Subject: Re: [PATCH] HID: Improve Windows Precision Touchpad detection.

On Thu, Nov 7, 2019 at 10:07 AM Blaž Hrastnik <[email protected]> wrote:
>
> I've submitted a test containing the Surface Book 2 descriptor.
>
> https://gitlab.freedesktop.org/libevdev/hid-tools/merge_requests/59

Thanks.

Patch is now queued in branch for-5.5/core.

Cheers,
Benjamin

>
> Blaž
>
> On Thu, 7 Nov 2019, at 17:48, Benjamin Tissoires wrote:
> > Hi Blaž,
> >
> > On Wed, Nov 6, 2019 at 12:03 PM Blaž Hrastnik <[email protected]> wrote:
> > >
> > > Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing
> > > data used to verify the touchpad as a Windows Precision Touchpad.
> > >
> > > 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> > > 0x09, 0xC5, // USAGE (Vendor Usage 0xC5)
> > > 0x15, 0x00, // LOGICAL_MINIMUM (0)
> > > 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> > > 0x75, 0x08, // REPORT_SIZE (8)
> > > 0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256))
> > > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> > >
> > > However, some devices, namely Microsoft's Surface line of products
> > > instead implement a "segmented device certification report" (usage 0xC6)
> > > which returns the same report, but in smaller chunks.
> > >
> > > 0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined)
> > > 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA)
> > > 0x09, 0xC6, // USAGE (Vendor usage for segment #)
> > > 0x25, 0x08, // LOGICAL_MAXIMUM (8)
> > > 0x75, 0x08, // REPORT_SIZE (8)
> > > 0x95, 0x01, // REPORT_COUNT (1)
> > > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> > > 0x09, 0xC7, // USAGE (Vendor Usage)
> > > 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff)
> > > 0x95, 0x20, // REPORT_COUNT (32)
> > > 0xb1, 0x02, // FEATURE (Data,Var,Abs)
> > >
> > > By expanding Win8 touchpad detection to also look for the segmented
> > > report, all Surface touchpads are now properly recognized by
> > > hid-multitouch.
> > >
> > > Signed-off-by: Blaž Hrastnik <[email protected]>
> > > ---
> >
> > This looks good to me.
> > We *could* shorten the ifs and make only one conditional, but I find
> > it this way more readable and future proof.
> >
> > There is just one last step required before we merge this: add a
> > regression test so we ensure we do not break it in the future.
> >
> > It should be merely a matter of sending a MR to
> > https://gitlab.freedesktop.org/libevdev/hid-tools.
> > It should consist in adding the report descriptor in the same way we
> > have
> > https://gitlab.freedesktop.org/libevdev/hid-tools/blob/master/tests/test_multitouch.py#L1656-1658.
> > Then, make sure an unpatched kernel breaks the multitouch test (sudo
> > pytest-3 -k 'multitouch and TestPTP') and that a patched kernel is
> > fixed.
> >
> > Cheers,
> > Benjamin
> >
> > > drivers/hid/hid-core.c | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > > index 63fdbf09b044..2af597cd5d65 100644
> > > --- a/drivers/hid/hid-core.c
> > > +++ b/drivers/hid/hid-core.c
> > > @@ -742,6 +742,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
> > > if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
> > > parser->global.report_size == 8)
> > > parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> > > +
> > > + if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
> > > + parser->global.report_size == 8)
> > > + parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
> > > }
> > >
> > > static void hid_scan_collection(struct hid_parser *parser, unsigned type)
> > > --
> > > 2.23.0
> > >
> >
> >