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

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

On Wed, Jan 21, 2026 at 02:58:03PM +0100, Mika Westerberg wrote:
> On Wed, Jan 21, 2026 at 11:13:36AM +0200, Andy Shevchenko wrote:
> > Mika, do you have any other insights, suggestions, comments?
> 
> I have not been following deeply what has been discussed so apologies if
> I'm missing something already stated.

Thanks for chiming in!

> 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...)


-- 
With Best Regards,
Andy Shevchenko