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

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

On Wed, Jan 21, 2026 at 04:54:43PM +0200, Andy Shevchenko wrote:
> > My understanding is that some models touchpad does not work if the idma64
> > driver is loaded but they do work if it is not. Also there is some sort of
> > interrupt flood coming from somewhere?
> > 
> > When idma64 is not present the toucpad works flawlessly?
> 
> On *old* kernels where idma64 blindly acknowledges all the interrupts.
> Fixed idma64 doesn't affect the IRQ storm because it's just a given
> fact on these laptops.
> 
> > Does it works in Windows?
> > 
> > I mean if it works in Windows and we also know it works in Linux without
> > idma64 then we can go with some sort of quirk (or better yet figure out
> > what is going on) to keep users touchpads working. I think this is much
> > better option than asking BIOS update from vendor which there is close to
> > zero possibility to happen in reality.
> 
> What kind of a quirk? Just to create a module that will request the same IRQ
> and always acknowledges it? Sounds to me like a heavily papering over solution
> TBH. (Yes, I assume it may be used only on DMI based enumeration only on the
> affected models, but still...)

Well I mean if touchpads actually worked prior this idma64 commit and now
they don't isn't that a regression? After that one commit touchpads don't
work anymore. I would much rather make sure users devices keep functional
even if it turns out to be hack of some sort. For example could be
blacklist idma64? Does that help?

Yes the interrupt flood still happens but if that does not affect the
toucpad then that's still better than non-functional touchpad IMO.