Hi Jonathan, On Mon, Nov 27, 2023 at 10:38:57AM -0600, Jonathan Denose wrote: > Hi Dmitry > > On Fri, Nov 24, 2023 at 10:45 PM Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > > > > Hi Jonathan, > > > > On Mon, Sep 25, 2023 at 04:33:20PM -0500, Jonathan Denose wrote: > > > The ThinkPad T14 Gen 1 touchpad works fine except that clicking > > > and dragging by tapping the touchpad or depressing the touchpad > > > do not work. Disabling PNP for controller setting discovery enables > > > click and drag without negatively impacting other touchpad features. > > > > I would like to understand more on how enabling PnP discovery for i8042 > > affects the touchpad. Do you see it using different interrupt or IO > > ports? What protocol does the touchpad use with/without PnP? If the > > protocol is the same, do you see difference in the ranges (pressure, > > etc) reported by the device? > > > > Thanks. > > > > -- > > Dmitry > > Without PnP discovery the touchpad is using the SynPS/2 protocol, with > PnP discovery, the touchpad is using the rmi4 protocol. Since the > protocols are different, so are the ranges but let me know if you > still want to see them. Thank you for this information. So it is not PnP discovery that appears harmful in your case, but rather that legacy PS/2 mode appears to be working better than RMI4 for the device in question. I will note that the original enablement of RMI4 for T14 was done by Hans in [1]. Later T14 with AMD were added to the list of devices that should use RMI4 [2], however this was reverted in [3]. Could you please tell me what exact device you are dealing with? What's it ACPI ID? [1] https://lore.kernel.org/all/20201005114919.371592-1-hdegoede@xxxxxxxxxx/ [2] https://lore.kernel.org/r/20220318113949.32722-1-snafu109@xxxxxxxxx [3] https://lore.kernel.org/r/20220920193936.8709-1-markpearson@xxxxxxxxxx Thanks. -- Dmitry
