On Mon, Apr 07, 2014 at 08:21:00PM -0700, Guenter Roeck wrote:Panther Point is Series 7 if I understand correctly, but the GPE0_STS
On 04/07/2014 07:48 PM, Matthew Garrett wrote:
You shouldn't need to install an SCI handler - the way the hardware will
generate an SCI is to raise a GPE. If you know which GPE the device
raises (my recollection is that for most Intel chipsets it's GPIO number
+ 0x10) then you can just call acpi_install_gpe_handler(). The problem
Sounds good. Do you by any chance have a pointer to some documentation
explaining this in some more detail ?
The SCI is just IRQ 9 - it tells the OS that there's a firmware event,
but in itself doesn't say what that event was. This is handled by the
platform setting bits in the GPE*_STS registers. The ACPI code reads
that and then dispatches the event to the appropriate handler. This will
typically be some ACPI code (declared by _Lxx and _Exx methods in the
ACPI tables - xx corresponds to the GPE number, L and E whether it's
level or edge triggered), but in some cases you want to install a
hardcoded event handler.
I've only got the 5-series docs to hand, and I can't remember whether
that's Panther Point, but you want to look at the definition of GPE0_STS
to figure out which hardware events cause which GPEs. GPEs 16 to 31
appear to correspond to GPIO 0 to 15, which is easy enough to handle.
is that the firmware may well already be using some of those GPIOs, andThe gpio-ich driver already has some magic to detect that condition - I
there's no easy way to tell. Checking the interrupt configuration isn't
sufficient, since some of them may just be used as outputs.
noticed that I can not request all GPIO pins on all hardware. Either case,
the gpio pins I am interested in are well defined on the hardware I am
dealing with, so I can be sure I won't step on some unexpected use.
Ok. As long as you don't reprogram anything by default, I think this
should be fine.