| Message ID | 1446199325-48095-1-git-send-email-mika.westerberg@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Oct 30, 2015 at 11:02 AM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > In Microsoft Surface3 the GPIO detecting lid state is shared between GPIO > event and operation region. Below is simplied version of the DSDT from > Surface3 including relevant parts: (...) > To be able to go through acpi_gpio->events list for operation region access > we need to make sure the list is properly initialized whenever GPIO chip is > registered. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=106571 > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> I wonder what an operation region is, maybe it's something you can eat. But I trust you Mika, so patch applied. Maybe I should get a surface, it seems cool. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Friday, October 30, 2015 09:17:41 PM Linus Walleij wrote: > On Fri, Oct 30, 2015 at 11:02 AM, Mika Westerberg > <mika.westerberg@linux.intel.com> wrote: > > > In Microsoft Surface3 the GPIO detecting lid state is shared between GPIO > > event and operation region. Below is simplied version of the DSDT from > > Surface3 including relevant parts: > (...) > > To be able to go through acpi_gpio->events list for operation region access > > we need to make sure the list is properly initialized whenever GPIO chip is > > registered. > > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=106571 > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > I wonder what an operation region is, maybe it's something you can eat. That's a way for AML to access things. Basically, if it wants to access a resource, it has to declare "I will be using X bytes at location Y in address space Z" and the OS is supposed to provide a handler for that. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c index 143a9bdbaa53..bbcac3af2a7a 100644 --- a/drivers/gpio/gpiolib-acpi.c +++ b/drivers/gpio/gpiolib-acpi.c @@ -304,7 +304,6 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) if (ACPI_FAILURE(status)) return; - INIT_LIST_HEAD(&acpi_gpio->events); acpi_walk_resources(handle, "_AEI", acpi_gpiochip_request_interrupt, acpi_gpio); } @@ -603,6 +602,25 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address, break; } } + + /* + * The same GPIO can be shared between operation region and + * event but only if the access here is ACPI_READ. In that + * case we "borrow" the event GPIO instead. + */ + if (!found && agpio->sharable == ACPI_SHARED && + function == ACPI_READ) { + struct acpi_gpio_event *event; + + list_for_each_entry(event, &achip->events, node) { + if (event->pin == pin) { + desc = event->desc; + found = true; + break; + } + } + } + if (!found) { desc = gpiochip_request_own_desc(chip, pin, "ACPI:OpRegion"); @@ -719,6 +737,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip) } acpi_gpio->chip = chip; + INIT_LIST_HEAD(&acpi_gpio->events); status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio); if (ACPI_FAILURE(status)) {
In Microsoft Surface3 the GPIO detecting lid state is shared between GPIO event and operation region. Below is simplied version of the DSDT from Surface3 including relevant parts: Scope (GPO0) { Name (_AEI, ResourceTemplate () { GpioInt (Edge, ActiveBoth, Shared, PullNone, 0x0000, "\\_SB.GPO0", 0x00, ResourceConsumer, , ) { // Pin list 0x004C } }) OperationRegion (GPOR, GeneralPurposeIo, Zero, One) Field (GPOR, ByteAcc, NoLock, Preserve) { Connection ( GpioIo (Shared, PullNone, 0x0000, 0x0000, IoRestrictionNone, "\\_SB.GPO0", 0x00, ResourceConsumer,,) { // Pin list 0x004C } ), HELD, 1 } Method (_E4C, 0, Serialized) // _Exx: Edge-Triggered GPE { If ((HELD == One)) { ^^LID.LIDB = One } Else { ^^LID.LIDB = Zero Notify (LID, 0x80) // Status Change } Notify (^^PCI0.SPI1.NTRG, One) // Device Check } } When GPIO 0x4c changes we call ASL method _E4C which tries to read HELD field (the same GPIO). This triggers following error on the console: ACPI Error: Method parse/execution failed [\_SB.GPO0._E4C] (Node ffff88013f4b4438), AE_ERROR (20150930/psparse-542) The error happens because ACPI GPIO operation region handler (acpi_gpio_adr_space_handler()) tries to acquire the very same GPIO which returns an error (-EBUSY) because the GPIO is already reserved for the GPIO event. Fix this so that we "borrow" the event GPIO if we find the GPIO belongs to an event. Allow this only for GPIOs that are read. To be able to go through acpi_gpio->events list for operation region access we need to make sure the list is properly initialized whenever GPIO chip is registered. Link: https://bugzilla.kernel.org/show_bug.cgi?id=106571 Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- drivers/gpio/gpiolib-acpi.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)