On Sun, Apr 29, 2018 at 9:35 PM, Tristian Celestin
<tristiancelestin@xxxxxxxxxxxx> wrote:
> I have a patch ready, but I don't know the underlying cause of the problem, and this is preventing from writing a meaningful commit message.
According to my understanding, the original intel-hid spec supported
0xC0 notification and events are reported by HDEM method, and an
update of "5 button array" added other notification numbers such as
0xce for power button; however, some BIOS failed to report 5 button
array is supported via HEBC method, and the DMI quirk was a workaround
to always enable 5 button array.
I personally think a commit message similar to c454a99d4ce1cebb is
good enough, but Andy or Darren will provide more feedbacks if they
think a refinement is necessary.
>
>
> On Sun, Apr 29, 2018, at 8:45 PM, Tristian Celestin wrote:
>>
>>
>>
>> On Mon, Apr 23, 2018, at 8:55 PM, Alex Hung wrote:
>>> On Mon, Apr 23, 2018 at 7:36 AM, Andy Shevchenko
>>> <andy.shevchenko@xxxxxxxxx> wrote:
>>>> 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.
>>
>> Thank you for the guidance. Will do.
>>
>>>>> 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;
>>>>> }
>>>
>>> Thanks for the work. This somehow sounds similar to Wacom MobileStudio
>>> Pro that we worked on before. A quirk was added to enable 5 button
>>> array, and the commit is c454a99d4ce1cebb.
>>>
>>> Could you please try to add a DMI entry in button_array_table[] and
>>> verify the power button again? If this works, we can use the DMI quirk
>>> instead.
>>
>> Thank you for the guidance. I added a DMI entry to button_array_table[] for the Latitude 5175, and the
>> tablet now also responds to short presses while suspended.
>>
>>>>>
>>>>> 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
>>>
>>>
>>>
>>> --
>>> Cheers,
>>> Alex Hung
--
Cheers,
Alex Hung
