Hi,
on two different Intel based POS machines where UARTs are crucial,
I see such messages (4.11.7 now, seen with older kernels, too):
[ 0.919239] ACPI: IRQ 4 override to edge, high
[ 0.919334] pnp 00:02: Plug and Play ACPI device, IDs PNP0501 (active)
[ 0.919697] ACPI: IRQ 3 override to edge, high
[ 0.919784] pnp 00:03: Plug and Play ACPI device, IDs PNP0501 (active)
[ 0.920154] ACPI: IRQ 11 override to edge, high
[ 0.920247] pnp 00:04: Plug and Play ACPI device, IDs PNP0501 (active)
[ 0.920449] pnp 00:05: Plug and Play ACPI device, IDs PNP0501 (disabled)
[ 0.920811] ACPI: IRQ 5 override to edge, high
[ 0.920908] pnp 00:06: Plug and Play ACPI device, IDs PNP0501 (active)
[ 0.921272] ACPI: IRQ 6 override to edge, high
[ 0.921363] pnp 00:07: Plug and Play ACPI device, IDs PNP0501 (active)
It seems that the PnP and the ACPI tables are inconsistent and ACPI wins.
Because of this, the UART IRQs don't work, write() or tcdrain() stalls.
Is there a kernel parameter that convinces the Linux ACPI to avoid
touching the PnP IRQs?
Thanks in advance,
Zolt?n B?sz?rm?nyi