On Wed, 2022-12-07 at 10:47 +0100, Rafael J. Wysocki wrote:
> On Wed, Dec 7, 2022 at 10:29 AM Bastien Nocera <hadess@xxxxxxxxxx>
> wrote:
> >
> > On Wed, 2022-12-07 at 10:12 +0100, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > >
> > > Evidently, Logitech Bluetooth Mouse M336/M337/M535 (0xb016) does
> > > not
> > > work when HID++ is enabled for it,
> >
> > This needs the output of the hidpp-list-features tool mentioned
> > earlier
> > in the thread so we can avoid words like "evidently" and provide
> > concrete proof.
>
> Well, so point me to a binary of this, please.
>
> > But why is it needed in this case?
>
> Because it doesn't work otherwise.
>
> > We purposefully try to avoid blanket
> > blocklists. The lack of HID++ can be probed, so the device should
> > work
> > just as it used to (if the fallback code works).
>
> No, because the hid-generic driver has no way to check that the probe
> function of your driver fails for this particular device. The
> probing
> of hid-generic will fail so long as the device matches the device ID
> list of any specific HID driver. With patch [1/2] from this series
> applied this is unless that specific driver has a ->match() callback
> rejecting the given device.
>
> You'd need a list of drivers that have been tried and failed
> somewhere
> for that and AFAICS no such list is present in the code.
This code will start the generic HID stack if the device doesn't
support HID++:
hidpp->supported_reports = hidpp_validate_device(hdev);
if (!hidpp->supported_reports) {
hid_set_drvdata(hdev, NULL);
devm_kfree(&hdev->dev, hidpp);
return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
}
But in your case the device supports HID++ enough to go past that, but
fails to get the HID++ version, which makes the driver think it's not
connected, and just bails.
> So a minimum fix for 6.1 that actually works for me is to add the
> non-working device to the blocklist. More sophisticated stuff can be
> done later.
>
> > We should only list devices that need special handling, and the
> > ones
> > that don't work once HID++ was probed unsuccessfully.
> >
> > > so add it to the list of devices
> > > that are not handled by logitech-hidpp.
> > >
> > > Fixes: 532223c8ac57 ("HID: logitech-hidpp: Enable HID++ for all
> > > the
> > > Logitech Bluetooth devices")
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > > ---
> > > drivers/hid/hid-logitech-hidpp.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > Index: linux-pm/drivers/hid/hid-logitech-hidpp.c
> > > =================================================================
> > > ==
> > > --- linux-pm.orig/drivers/hid/hid-logitech-hidpp.c
> > > +++ linux-pm/drivers/hid/hid-logitech-hidpp.c
> > > @@ -4274,6 +4274,7 @@ static const struct hid_device_id unhand
> > > { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
> > > USB_DEVICE_ID_LOGITECH_HARMONY_PS3) },
> > > /* Handled in hid-generic */
> > > { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
> > > USB_DEVICE_ID_LOGITECH_DINOVO_EDGE_KBD) },
> > > + { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH, 0xb016) },
> > > {}
> > > };
