On Sun, Apr 22, 2018 at 1:25 AM, Tristian Celestin
<tristiancelestin@xxxxxxxxxxxx> wrote:
Thanks for the patch.
First of all, please, include all PDx86 maintainers to the discussion as well.
Second, please, use `git send-email` tool to send patches, it avoids
attachments.
> I am running Fedora 28 and Android-x86 on a Dell Latitude 5175 tablet. The
> power button functionality is driven by the intel-hid driver. I am using
> kernel version 4.16.
>
> Currently, the intel-hid driver does not supply a KEY_POWER up event in cases
> where the platform doesn't expose the 5-button array. Without this patch, the
> power button can't reliably respond when the platform is running Android.
>
> When running Fedora, I can use the power button to suspend and resume the
> tablet. I can initiate this suspend by short-pressing the power button for a
> second, and can resume it using another short-press.
>
> When running Android-x86, I can only short-press the power button once. After
> the press, the button seems to no longer respond. This is problematic when
> using a short-press to initiate a suspend, since a subsequent short press will
> not wake the tablet.
>
> I used getevent to display the KeyEvents[1] detected by Android, and a
> combination of 'cat /proc/kmsg' and debug statements in the intel-hid driver
> to display the events generated by the driver. I found the block in the intel-
> hid driver that generates power button events for my device. On line 253 of
> intel-hid.c:
>
> if (!priv->array) {
> if (event == 0xce) {
> input_report_key(priv->input_dev, KEY_POWER, 1);
> input_sync(priv->input_dev);
> return;
> }
>
> if (event == 0xcf)
> return;
> }
>
> When I short-press the power button, intel-hid produces a KEY_POWER down
> event, but doesn't produce a KEY_POWER up event when I release the power
> button. Suppose intel-hid has been mapped to the input device /dev/input/
> event19. Then, on Android-x86, the command "getevent -lt" produces the
> following output:
>
> /dev/input/event19: EV_KEY KEY_POWER DOWN
> /dev/input/event19: EV_SYN SYN_REPORT 00000000
>
> Subsequent presses produced no output for that input device.
>
> When I added a call to input_report_key(...) and input_sync(...) on the
> KEY_POWER up event in the intel-hid driver, I could repeatedly short-press the
> power button and have Android respond appropriately, including resuming the
> device from suspend. My hunch as to why this is the case is that Android needs
> a paired KEY_POWER DOWN and UP event before it will handle the press.
WRT, patch contents:
- please, do a proper commit message
- while it has crucial semantic mistake (missing {}) it suddenly works
because nothing behind the condition you had touched
- I would rather unify conditionals, though I would like to hear from
Alex and Dmitry if it's fine to do what you are trying to do in the
patch
--
With Best Regards,
Andy Shevchenko
