On Fri, May 14 2021 at 13:58, Maximilian Luz wrote:
On 5/14/21 9:41 PM, Sachi King wrote: I'd assume that _some_ sort of interrupt setup is done by the BIOS/UEFI. The UEFI on those devices is fairly well-featured, with touch support via SPI and all. Furthermore, keyboard (also supported in the device's UEFI) is handled via a custom UART protocol. Unless they rely on polling for all of that, I believe they'd have to set up some interrupts.
Polling would be truly surprising.
Although, as you mention later on, that could also be handled via the IOAPIC and the PIC is actually not supposed to be used. Maybe some legacy component that never got tested and just broke with some new hardware/firmware revision without anyone noticing? And since Linux still seems to rely on that, we might be the first to notice.
That's a valid assumption. As I said, we can make IOAPIC work even w/o PIC. I'll have a look how much PIC assumptions are still around.
Thanks,
tglx