Hi,

sorry for the inconvenience this change has caused.

On 10/5/19 12:55 PM, Hans de Goede wrote:
Note ideally this seamingly unrelated change would have been made in a
separate commit, with a message explaining the what and why of this
change.

Would I have known the impact, then yes. This change was added due to
some reported instances where it seems that soc_button_array would
occasionally load on MSHW0040 before the GPIO controller was ready,
causing power and volume buttons to not work.

I guess this change may have been added to deal with -EPROBE_DEFER errors,

Correct. After a comment mentioned that gpiod_get() returning
-EPROBE_DEFER would be the proper way to detect this, I decided on this
change.

Might I suggest the following addition:

Signed-off-by: Maximilian Luz <luzmaximil...@gmail.com>
---
 drivers/input/misc/soc_button_array.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/input/misc/soc_button_array.c 
b/drivers/input/misc/soc_button_array.c
index 97e3639e99d0..a0f0c977b790 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -92,11 +92,18 @@ soc_button_device_create(struct platform_device *pdev,
                        continue;
gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
-               if (gpio < 0 && gpio != -ENOENT) {
-                       error = gpio;
-                       goto err_free_mem;
-               } else if (!gpio_is_valid(gpio)) {
-                       /* Skip GPIO if not present */
+               if (!gpio_is_valid(gpio)) {
+                       /*
+                        * Skip GPIO if not present. Note we deliberately
+                        * ignore -EPROBE_DEFER errors here. On some devices
+                        * Intel is using so called virtual GPIOs which are not
+                        * GPIOs at all but some way for AML code to check some
+                        * random status bits without need a custom opregion.
+                        * In some cases the resources table we parse points to
+                        * such a virtual GPIO, since these are not real GPIOs
+                        * we do not have a driver for these so they will never
+                        * show up, therefor we ignore -EPROBE_DEFER.
+                        */
                        continue;
                }
@@ -429,6 +436,14 @@ static int soc_device_check_MSHW0040(struct device *dev) dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev); + /*
+        * Explicitly check if GPIO controller is ready. This check is done here
+        * to avoid issues with virtual GPIOs on other chips, as elaborated 
above.
+        * We are at least expecting one GPIO pin for the power button (index 
0).
+        */
+       if (soc_button_lookup_gpio(dev, 0) == -EPROBE_DEFER)
+               return -EPROBE_DEFER;
+
        return 0;
 }
--
2.23.0

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