This is a note to let you know that I've just added the patch titled

driver core: platform: return -ENXIO for missing GpioInt

to my driver-core git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git in the driver-core-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 46c42d844211ef5902e32aa507beac0817c585e9 Mon Sep 17 00:00:00 2001

From: Brian Norris briannorris@chromium.org Date: Mon, 29 Jul 2019 13:49:54 -0700 Subject: driver core: platform: return -ENXIO for missing GpioInt

Commit daaef255dc96 ("driver: platform: Support parsing GpioInt 0 in platform_get_irq()") broke the Embedded Controller driver on most LPC Chromebooks (i.e., most x86 Chromebooks), because cros_ec_lpc expects platform_get_irq() to return -ENXIO for non-existent IRQs. Unfortunately, acpi_dev_gpio_irq_get() doesn't follow this convention and returns -ENOENT instead. So we get this error from cros_ec_lpc:

couldn't retrieve IRQ number (-2)

I see a variety of drivers that treat -ENXIO specially, so rather than fix all of them, let's fix up the API to restore its previous behavior.

I reported this on v2 of this patch:

https://lore.kernel.org/lkml/20190220180538.GA42642@google.com/

but apparently the patch had already been merged before v3 got sent out:

https://lore.kernel.org/lkml/20190221193429.161300-1-egranata@chromium.org/

and the result is that the bug landed and remains unfixed.

I differ from the v3 patch by: * allowing for ret==0, even though acpi_dev_gpio_irq_get() specifically documents (and enforces) that 0 is not a valid return value (noted on the v3 review) * adding a small comment

Reported-by: Brian Norris briannorris@chromium.org Reported-by: Salvatore Bellizzi salvatore.bellizzi@linux.seppia.net Cc: Enrico Granata egranata@chromium.org Cc: stable@vger.kernel.org Fixes: daaef255dc96 ("driver: platform: Support parsing GpioInt 0 in platform_get_irq()") Signed-off-by: Brian Norris briannorris@chromium.org Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Acked-by: Enrico Granata egranata@google.com Link: https://lore.kernel.org/r/20190729204954.25510-1-briannorris@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/base/platform.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 506a0175a5a7..ec974ba9c0c4 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -157,8 +157,13 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) * the device will only expose one IRQ, and this fallback * allows a common code path across either kind of resource. */ - if (num == 0 && has_acpi_companion(&dev->dev)) - return acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); + if (num == 0 && has_acpi_companion(&dev->dev)) { + int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); + + /* Our callers expect -ENXIO for missing IRQs. */ + if (ret >= 0 || ret == -EPROBE_DEFER) + return ret; + }

return -ENXIO; #endif