Hi,

On 5/4/20 9:39 AM, Benjamin Tissoires wrote:

Hi Hans,

On Sat, May 2, 2020 at 2:59 PM Hans de Goede [off-list ref] wrote:

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Hi,

On 5/1/20 8:20 PM, Hans de Goede wrote:

quoted

Hi,

On 5/1/20 11:56 AM, Hans de Goede wrote:

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The touchpad on the Dell Venue 11 Pro 7130's keyboard-dock is multi-touch
capable, using HID_GROUP_MULTITOUCH_WIN_8 and the hid-multitouch driver
correctly binds to it.

But instead of getting multi-touch HID input reports we still get mouse
input reports and corresponding linux input (evdev) node events.

Unloading and reloading the hid-multitouch driver works around this.

Adding the MT_QUIRK_FORCE_GET_FEATURE quirk to the MT_CLS_WIN_8 quirks
makes the driver work correctly the first time it is loaded.

I've chosen to add this quirk to the generic MT_CLS_WIN_8 quirks
because it seems unlikely that this quirk will causes problems for
other MT_CLS_WIN_8 devices and if this device needs it other Win 8
compatible devices might need it too.

Signed-off-by: Hans de Goede <redacted>

Self nack for now, there are more issues with this detachable keyboard,
it sometimes does not work after being unplugged and replugged again
USB_QUIRK_DELAY_INIT seems to help a bit, but is not a total solution...

Dell has some firmware updates for the kbd. So I'll install Windows and
then update the firmware and we'll see from there.

So after installing Windows it turns out that the kbd-dock firmware was
already fully up2date, what fun.

So it took me quite a long time to get to the bottom of this.

The problem is that the Dell K12A kbd-dock needs a HID_QUIRK_NO_INIT_REPORTS
quirk; or maybe both of HID_QUIRK_NO_INIT_REPORTS|HID_QUIRK_NOGET I've tested

I think this is a regression introduced by the high res scrolling
patch. I have been notified that the new code actually does fetch all
features on connect, which many devices do not support.

I don't think I received the patch related to that, but basically the
problematic code is at
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/hid/hid-input.c#n1558

The issue is that we should only fetch the current report if the
HID_GD_RESOLUTION_MULTIPLIER is present. Or we break things.

I don't think that this is related to the high-res scrolling stuff.

The errors I'm seeing on a bad hotplug are coming from
drivers/hid/hid-multitouch.c: mt_get_feature()

Also quite a few other multi-touch devices have a HID_QUIRK_NO_INIT_REPORTS
quirk, at least a bunch of surface keyboards do; and if I'm reading the
git log correctly then at one point in time we used to have a
HID_QUIRK_NO_INIT_REPORTS for at least some of the multi-touch classes
inside hid-multitouch.c. At least there is a commit titled:

"HID: multitouch: do not set HID_QUIRK_NO_INIT_REPORTS"

Which suggests that one point we did set it inside the multi-touch
driver; and I'm wondering since a bunch of surface keyboards need this
if setting this inside the multi-touch driver would not get us closer
to windows behavior.

Anyways if you have an alternative fix you want me to test, let me know.

Regards,

Hans

Cheers,
Benjamin

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with the later version and that fixes both the touchpad initially being
stuck in mouse emulation and the dock misbehaving after a hot unplug + replug.

I suspect I really only need HID_QUIRK_NO_INIT_REPORTS, I will retest with
that and submit a new patch replacing this one.

Somewhat related: to make space for the Windows install I nuked the old
Fedora 27 install which was on the machine and after installing Windows
I did a fresh Fedora 32 install in the space which I left free when
installing Windows.

This causes an interesting new problem. The touchpad worked fine
(with the quirk) in gdm, but it would stop working when I logged into
a user GNOME-session.  It took me a while to get to the bottom of
this. The problem is that the usersession ends up dbus activating
fwupd (probably through gnome-software) and fwupd does some probe
of the touchpad which puts it in a mode where it no longer generates
any events.

sudo rpm -e fwupd gnome-software

Works around this, so not a HID bug, but definitely something to keep
an eye out for if we get similar bug reports on other devices.

I will mail the fwupd maintainer about this with you in the Cc.
Note this is an unrelated issue really, but I thought you
should be aware of this.

Regards,

Hans

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---
   drivers/hid/hid-multitouch.c | 1 +
   1 file changed, 1 insertion(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 362805ddf377..f9c0429e7348 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c

@@ -265,6 +265,7 @@ static const struct mt_class mt_classes[] = {
               MT_QUIRK_IGNORE_DUPLICATES |
               MT_QUIRK_HOVERING |
               MT_QUIRK_CONTACT_CNT_ACCURATE |
+            MT_QUIRK_FORCE_GET_FEATURE |
               MT_QUIRK_STICKY_FINGERS |
               MT_QUIRK_WIN8_PTP_BUTTONS,
           .export_all_inputs = true },