Re: [REGRESSION][BISECTED] Lenovo IdeaPad touchpad does not work when idma64 is present in initramfs

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Feb 04, 2026 at 10:53:57AM -0500, correctmost wrote:
> On Wed, Feb 4, 2026, at 10:34 AM, Mika Westerberg wrote:
> > On Wed, Feb 04, 2026 at 10:12:57AM -0500, correctmost wrote:
> >> > I will try to debug the config issue and retest the touchpad with the 
> >> > proper config changes.
> >> 
> >> After fixing the config issue, I now see "Dynamic Preempt: voluntary" in
> >> the dmesg output.  I also see "# CONFIG_HID_BPF is not set" in
> >> /proc/config.gz.
> >> 
> >> The "probe with driver hid-generic failed with error -22" message is
> >> still present and the touchpad doesn't work (full log attached).
> >
> > Thanks!
> >
> > I don't see any other way than adding even more debug. It really should at
> > least be able to parse the report descriptor as that's exactly the same as
> > in working case but let's try to figure why it fails. Can you add again on
> > top of everything this one:
> 
> The attached log has the added hid debug lines.

Thanks!

I now realized that the dump of the report descriptor truncates it into 64
bytes so it can actually contain whatever crap that the controller read and
this is probably why the HID parser fails. My apologies.

I think at this point there is not much we can do :( You have the
workaround, to put everything in the initramfs (or built into the kernel
image), right? We have asked schematics from Lenovo but there is no
guarantee we get them and I think those are needed to figure out how the
touchpad is connected.