On 04/07/2014 08:31 PM, Matthew Garrett wrote:
On Mon, Apr 07, 2014 at 08:21:00PM -0700, Guenter Roeck wrote:
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.
Panther Point is Series 7 if I understand correctly, but the GPE0_STS
definition is the same.
That should get me started - thanks again!
Guenter
is that the firmware may well already be using some of those GPIOs, and
there's no easy way to tell. Checking the interrupt configuration isn't
sufficient, since some of them may just be used as outputs.
The gpio-ich driver already has some magic to detect that condition - I
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.
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