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

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

On Mon, Feb 02, 2026 at 06:16:02AM -0500, correctmost wrote:
> > Could you drop the above hack again so that it should "fail". Then build
> > the kernel with CONFIG_PREEMPT_VOLUNTARY=y and add the below hack. Perhaps
> > this is just lucky timing? Please try a couple of boots and make sure the
> > results are the same each time.
> 
> I cold booted five times and the touchpad did not work during any of those boots.

Thanks!

> I noticed that the "probe with driver" failure reports -22 instead of -110 now:
> 
> [   33.023932] i2c_hid_acpi i2c-ELAN06FA:00: Report Descriptor: 05 01 09 02 a1 01 85 01 09 01 a1 00 05 09 19 01 29 02 15 00 25 01 75 01 95 02 81 02 95 06 81 03 05 01 09 30 09 31 15 81 25 7f 75 08 95 02 81 06 75 08 95 05 81 03 c0 06 00 ff 09 01 85 0e 09 c5
> [   33.026070] hid-generic 0018:04F3:327E.0001: item fetching failed at offset 638/675
> [   33.027573] hid-generic 0018:04F3:327E.0001: probe with driver hid-generic failed with error -22
> ...
> [   33.183959] hid-multitouch 0018:04F3:327E.0001: item fetching failed at offset 638/675
> [   33.183975] hid-multitouch 0018:04F3:327E.0001: probe with driver hid-multitouch failed with error -22
> 

This is really odd because "item fetching" is not really accessing any
hardware bus - it just parses the descriptor and the descriptor looks fine
to me (and this is the same as in case of working run):

Usage Page (Generic Desktop)
Usage (Generic Desktop.Mouse)
Collection (1)
  Report ID (1)
  Usage (Generic Desktop.Pointer)
  Collection (0)
    Usage Page (Button)
    Usage Minimum (1)
    Usage Maximum (2)
    Logical Minimum (0)
    Logical Maximum (1)
    Report Size (1)
    Report Count (2)
    Input (2)
    Report Count (6)
    Input (3)
    Usage Page (Generic Desktop)
    Usage (Generic Desktop.X)
    Usage (Generic Desktop.Y)
    Logical Minimum (129)
    Logical Maximum (127)
    Report Size (8)
    Report Count (2)
    Input (6)
    Report Size (8)
    Report Count (5)
    Input (3)
  End Collection (0)
  Usage Page (Vendor Defined Page 1)
  Usage (Vendor Defined Page 1.Vendor Usage 1)
  Report ID (14)
  Usage (Vendor Defined Page 1.00c5)

I noticed  you still have:

[    0.069726] Dynamic Preempt: full

Can you change that in .config to:

CONFIG_PREEMPT_VOLUNTARY=y

Also let's add on top of everything one more hack patch, just in case ;-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index ed90858a27b7..0297ebedb802 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -371,7 +371,7 @@ static const struct acpi_device_id i2c_acpi_force_100khz_device_ids[] = {
 	 * a 400KHz frequency. The root cause of the issue is not known.
 	 */
 	{ "DLL0945", 0 },
-	{ "ELAN06FA", 0 },
+//	{ "ELAN06FA", 0 },
 	{}
 };