Re: Regression: SYNA3602 I2C touchpad broken in Linux 6.17.7 (works in 6.17.6 and previous versions)

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Mon, Dec 08, 2025 at 02:54:20PM +0100, Thorsten Leemhuis wrote:
> On 12/8/25 13:13, Vijay wrote:
> > 
> > Yes, the touchpad is not working in 6.18 also, getting the same errors
> > as mentioned previously, 
> 
> That's really good to know, thx!
> 
> Thing is: I fear that nobody will look into this, unless you or somebody
> else affected checks which change broke things. Benjamin mentioned three
> you could try reverting in 6.17.y; alternatively, perform a bisection in
> 6.17.y. For details, see:
> https://docs.kernel.org/admin-guide/verify-bugs-and-bisect-regressions.html

Might be related:
https://bugzilla.kernel.org/show_bug.cgi?id=219799

> > On Thu, 4 Dec 2025 at 20:40, Thorsten Leemhuis
> > <regressions@leemhuis.info <mailto:regressions@leemhuis.info>> wrote:
> > 
> >     Lo!
> > 
> >     @AM Vijay: 6.17.y will be EOL in about ten days, so this is unlikely to
> >     get fixed there. The big question is:
> > 
> >     Is 6.18 affected?
> > 
> >     If it is, we need your help identifying want went wrong; if not, then
> >     it's likely not worth looking closer into this
> > 
> >     Ciao, Thorsten
> > 
> >     On 11/28/25 09:05, Benjamin Tissoires wrote:
> >     > Hi,
> >     >
> >     > On Fri, Nov 28, 2025 at 7:40 AM Vijay <vijayg0127@gmail.com
> >     <mailto:vijayg0127@gmail.com>> wrote:
> >     >>
> >     >> Hello,
> >     >>
> >     >> I would like to report a regression in the Linux kernel affecting
> >     I2C-HID
> >     >> touchpads that run through the Intel ISH + DesignWare I2C controller.
> >     >>
> >     >> Hardware:
> >     >> - Laptop: Infinix Y4 Max
> >     >> - CPU: Intel (13th gen core i5)
> >     >> - Touchpad: SYNA3602:00 093A:35ED (I2C HID)
> >     >> - Bus path: SYNA3602 → i2c_designware → Intel ISH → HID
> >     >> - OS: Linux (Arch/CachyOS)
> >     >> - Kernel config: Default distro config
> >     >>
> >     >> Regression summary:
> >     >> - Touchpad works perfectly in Linux 6.17.6 and below versions
> >     >> - Touchpad stops working in Linux 6.17.7 and all newer versions
> >     (6.17.8, 6.17.9, etc.)
> >     >> - Desktop environment does not matter (Hyprland/GNOME both fail)
> >     >> - The failure happens before userspace loads
> >     >> - Touchpad also works fine in Linux 6.12 LTS
> >     >>
> >     >> This is a kernel-level regression introduced between:
> >     >>     Good: Linux 6.17.6
> >     >>     Bad:  Linux 6.17.7
> >     >>
> >     >> **Dmesg logs from broken kernel (6.17.7 and newer):**
> >     >>
> >     >>     i2c-SYNA3602:00: can't add hid device: -110
> >     >>     hid_sensor_hub: reading report descriptor failed
> >     >>     intel-hid INTC1078:00: failed to enable HID power button
> >     >
> >     > Looks like i2c-hid can't even communicate with any I2C device, so this
> >     > is slightly worrying.
> >     >
> >     >>
> >     >> And the DesignWare I2C controller logs around the failure:
> >     >>     i2c_designware 0000:00:15.0: controller timed out
> >     >>     i2c_designware 0000:00:15.0: lost arbitration
> >     >>     i2c_designware 0000:00:15.0: transfer aborted (status = -110)
> >     >>
> >     >> These errors appear only on 6.17.7+ and not on 6.17.6.
> >     >>
> >     >> On working versions (6.17.6 and 6.12 LTS), the touchpad
> >     initializes normally:
> >     >>
> >     >>     input: SYNA3602:00 093A:35ED Touchpad as /devices/.../input/
> >     inputX
> >     >>     hid-multitouch: I2C HID v1.00 device initialized
> >     >>     i2c_designware 0000:00:15.0: controller operating normally
> >     >>
> >     >> This narrow regression window should make it possible to identify
> >     the offending
> >     >> change in either:
> >     >> - HID core
> >     >> - I2C-HID
> >     >> - Intel ISH HID
> >     >> - DesignWare I2C controller
> >     >> - ACPI timing changes
> >     >>
> >     >> I can provide:
> >     >> - Full dmesg (working and broken)
> >     >> - acpidump
> >     >
> >     > Are you running on a full vanilla kernel?
> >     >
> >     > The changelog between 6.17.6 and 6.17.7 is rather small, so it should
> >     > be easy enough to bisect and get the offending commit.
> >     >
> >     > I have my suspicions on:
> >     > f1971d5ba2ef ("genirq/manage: Add buslock back in to enable_irq()")
> >     > b990b4c6ea6b ("genirq/manage: Add buslock back in to
> >     __disable_irq_nosync()")
> >     > 3c97437239df ("genirq/chip: Add buslock back in to irq_set_handler()")
> >     >
> >     > Because anything else is unrelated to any component involved in
> >     i2c-hid.
> >     > (But that's also assuming you are running vanilla kernels without any
> >     > extra patches.)
> >     >
> >     > OTOH, I've booted a 6.17.8 and 6.17.7 shipped by Fedora and I don't
> >     > see any issues related to i2c-hid, so those 3 commits might not be the
> >     > culprits.

> >     >> Please let me know what additional data is needed.
> >     >
> >     > Can you do a bisect between v6.17.7 and v6.17.6?

-- 
With Best Regards,
Andy Shevchenko