linux-kernel - Re: [PATCH v4] Support intel-vbtn based tablet mode switch

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Date:   Fri, 26 Jan 2018 12:09:01 +0100
From:   Marco Martin <notmart@...il.com>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Matthew Garrett <mjg59@...f.ucam.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Bhushan Shah <bhush94@...il.com>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Mario Limonciello <mario.limonciello@...l.com>,
        Mario Limonciello <mario_limonciello@...l.com>
Subject: Re: [PATCH v4] Support intel-vbtn based tablet mode switch

On Fri, Jan 26, 2018 at 11:52 AM, Pali Rohár <pali.rohar@...il.com> wrote:
> On Friday 26 January 2018 10:45:55 Marco Martin wrote:
>> On martedì 23 gennaio 2018 16:18:24 CET Marco Martin wrote:
>> > Some laptops such as Dell Inspiron 7000 series have the
>> > tablet mode switch implemented in Intel ACPI,
>> > the events to enter and exit the tablet mode are 0xCC and 0xCD
>> >
>> > CC: platform-driver-x86@...r.kernel.org
>> > CC: Matthew Garrett <mjg59@...f.ucam.org>
>> > CC: "Pali Rohár" <pali.rohar@...il.com>
>> > CC: Darren Hart <dvhart@...radead.org>
>> > CC: Mario Limonciello <mario_limonciello@...l.com>
>> > CC: Andy Shevchenko <andy@...radead.org>
>> >
>> > Signed-off-by: Marco Martin <notmart@...il.com>
>> > ---
>> >  drivers/platform/x86/intel-vbtn.c | 21 +++++++++++++++++++++
>> >  1 file changed, 21 insertions(+)
>> >
>> > diff --git a/drivers/platform/x86/intel-vbtn.c
>> > b/drivers/platform/x86/intel-vbtn.c index 58c5ff3..64b4b34 100644
>> > --- a/drivers/platform/x86/intel-vbtn.c
>> > +++ b/drivers/platform/x86/intel-vbtn.c
>> > @@ -26,6 +26,9 @@
>> >  #include <linux/suspend.h>
>> >  #include <acpi/acpi_bus.h>
>> >
>> > +/* When NOT in tablet mode, VBDS has the flag 0x40 */
>> > +#define TABLET_MODE_FLAG 0x40
>> > +
>> >  MODULE_LICENSE("GPL");
>> >  MODULE_AUTHOR("AceLan Kao");
>> >
>> > @@ -42,6 +45,8 @@ static const struct key_entry intel_vbtn_keymap[] = {
>> >     { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },          /* volume-up key release */
>> >     { KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },           /* volume-down key press */
>> >     { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },        /* volume-down key release */
>> > +   { KE_SW,  0xCC, { .sw = { SW_TABLET_MODE, 1 } } }, /* Tablet mode in */
>> > +   { KE_SW,  0xCD, { .sw = { SW_TABLET_MODE, 0 } } }, /* Tablet mode out */
>> >     { KE_END },
>> >  };
>> >
>> > @@ -88,6 +93,7 @@ static void notify_handler(acpi_handle handle, u32 event,
>> > void *context)
>> >
>> >  static int intel_vbtn_probe(struct platform_device *device)
>> >  {
>> > +   struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
>> >     acpi_handle handle = ACPI_HANDLE(&device->dev);
>> >     struct intel_vbtn_priv *priv;
>> >     acpi_status status;
>> > @@ -110,6 +116,21 @@ static int intel_vbtn_probe(struct platform_device
>> > *device) return err;
>> >     }
>> >
>> > +   status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
>> > +   /* VGBS being present and returning something means
>> > +    * we have a tablet mode switch
>> > +    */
>> > +   if (ACPI_SUCCESS(status)) {
>> > +           union acpi_object *obj = vgbs_output.pointer;
>> > +
>> > +           if (obj && obj->type == ACPI_TYPE_INTEGER) {
>> > +                   input_set_capability(priv->input_dev, EV_SW, SW_TABLET_MODE);
>> > +                   input_report_switch(priv->input_dev,
>> > +                                                           SW_TABLET_MODE,
>> > +                                                           !(obj->integer.value & TABLET_MODE_FLAG));
>> > +           }
>> > +   }
>> > +
>> >     status = acpi_install_notify_handler(handle,
>> >                                          ACPI_DEVICE_NOTIFY,
>> >                                          notify_handler,
>>
>> Is there still something to change in this version of the patch?
>
> Yes, I already wrote it in thread for older patch version. Calling
> input_set_capability() is not needed at all because all capabilities are
> already set by sparse_keymap_setup() function.

ah, sorry, i somehow missed the answer.
Wouldn't this cause a problem tough? it was querying VGBS to add the
switch capability just conditionally
on models which actually have it, so now being in sparse_keymap, all
will have that switch available even if not there.
Now, if this is fine (after all that switch would never be triggered
on such hardware) i can go forward removing all of that so the patch
becomes a neat two-liner.

--
Marco Martin