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Date: Tue, 19 Jul 2016 04:48:16 +0000
From: "Zheng, Lv" <lv.zheng@...el.com>
To: Benjamin Tissoires <benjamin.tissoires@...il.com>
CC: "Wysocki, Rafael J" <rafael.j.wysocki@...el.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
"Brown, Len" <len.brown@...el.com>, Lv Zheng <zetalog@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
"Bastien Nocera:" <hadess@...ess.net>,
linux-input <linux-input@...r.kernel.org>
Subject: RE: [PATCH v3 1/2] ACPI / button: Add KEY_LID_CLOSE for new usage
model
Hi, Benjamin
> From: Benjamin Tissoires [mailto:benjamin.tissoires@...il.com]
> Subject: Re: [PATCH v3 1/2] ACPI / button: Add KEY_LID_CLOSE for new
> usage model
>
> Hi,
>
> On Tue, Jul 12, 2016 at 12:17 PM, Lv Zheng <lv.zheng@...el.com> wrote:
> > There are many AML tables reporting wrong initial lid state, and some of
> > them never reports lid open state. As a proxy layer acting between, ACPI
> > button driver is not able to handle all such cases, but need to re-define
> > the usage model of the ACPI lid. That is:
> > 1. It's initial state is not reliable;
> > 2. There may not be an open event;
> > 3. Userspace should only take action against the close event which is
> > reliable, always sent after a real lid close.
> > This patch adds a new input key event so that the new userspace
> programs
> > can use it to handle this usage model correctly. And in the meanwhile, no
> > old programs will be broken by the userspace changes.
> > This patch also adds a button.lid_event_type parameter to allow the
> users
> > to switch between the 2 event types.
>
> I think we are getting closer to what would be acceptable for
> user-space, but I still have a few comments:
[Lv Zheng]
OK.
>
> >
> > Signed-off-by: Lv Zheng <lv.zheng@...el.com>
> > Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
> > Cc: Benjamin Tissoires <benjamin.tissoires@...il.com>
> > Cc: Bastien Nocera: <hadess@...ess.net>
> > Cc: linux-input@...r.kernel.org
> > ---
> > drivers/acpi/button.c | 109 +++++++++++++++++++++++++--
> -----
> > include/uapi/linux/input-event-codes.h | 6 ++
> > 2 files changed, 91 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> > index 148f4e5..1298ef8 100644
> > --- a/drivers/acpi/button.c
> > +++ b/drivers/acpi/button.c
> > @@ -57,6 +57,9 @@
> > #define ACPI_BUTTON_LID_INIT_OPEN 0x01
> > #define ACPI_BUTTON_LID_INIT_METHOD 0x02
> >
> > +#define ACPI_BUTTON_LID_EVENT_KEY 0x00
> > +#define ACPI_BUTTON_LID_EVENT_SWITCH 0x01
> > +
> > #define _COMPONENT ACPI_BUTTON_COMPONENT
> > ACPI_MODULE_NAME("button");
> >
> > @@ -110,6 +113,7 @@ struct acpi_button {
> > static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
> > static struct acpi_device *lid_device;
> > static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
> > +static u8 lid_event_type = ACPI_BUTTON_LID_EVENT_SWITCH;
> >
> > /* --------------------------------------------------------------------------
> > FS Interface (/proc)
> > @@ -136,8 +140,17 @@ static int acpi_lid_notify_state(struct
> acpi_device *device, int state)
> > int ret;
> >
> > /* input layer checks if event is redundant */
> > - input_report_switch(button->input, SW_LID, !state);
> > - input_sync(button->input);
> > + if (lid_event_type == ACPI_BUTTON_LID_EVENT_SWITCH) {
> > + input_report_switch(button->input, SW_LID, !state);
> > + input_sync(button->input);
> > + }
> > + if (lid_event_type == ACPI_BUTTON_LID_EVENT_KEY &&
> > + !state) {
> > + input_report_key(button->input, KEY_LID_CLOSE, 1);
> > + input_sync(button->input);
> > + input_report_key(button->input, KEY_LID_CLOSE, 0);
> > + input_sync(button->input);
> > + }
> >
> > if (state)
> > pm_wakeup_event(&device->dev, 0);
> > @@ -292,6 +305,9 @@ static int acpi_lid_update_state(struct
> acpi_device *device)
> >
> > static void acpi_lid_initialize_state(struct acpi_device *device)
> > {
> > + if (lid_event_type == ACPI_BUTTON_LID_EVENT_KEY)
> > + return;
> > +
> > switch (lid_init_state) {
> > case ACPI_BUTTON_LID_INIT_OPEN:
> > (void)acpi_lid_notify_state(device, 1);
> > @@ -436,6 +452,7 @@ static int acpi_button_add(struct acpi_device
> *device)
> >
> > case ACPI_BUTTON_TYPE_LID:
> > input_set_capability(input, EV_SW, SW_LID);
> > + input_set_capability(input, EV_KEY, KEY_LID_CLOSE);
>
> Here you are basically exporting the 2 input events but only update
> one of the 2. It will confuse userspace and it is generally better not
> to export unused input codes.
[Lv Zheng]
I just do not know if it is proper to clear the capability during runtime via module parameters.
>
> However, as I'll say below, I think we should keep the code that way here.
[Lv Zheng]
Great. So we needn't think about input_clear_capability().
>
>
> > break;
> > }
> >
> > @@ -475,35 +492,49 @@ static int acpi_button_remove(struct
> acpi_device *device)
> >
> > static int param_set_lid_init_state(const char *val, struct kernel_param
> *kp)
> > {
> > - int result = 0;
> > -
> > - if (!strncmp(val, "open", sizeof("open") - 1)) {
> > - lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
> > - pr_info("Notify initial lid state as open\n");
> > - } else if (!strncmp(val, "method", sizeof("method") - 1)) {
> > - lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
> > - pr_info("Notify initial lid state with _LID return value\n");
> > - } else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
> > - lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
> > - pr_info("Do not notify initial lid state\n");
> > - } else
> > - result = -EINVAL;
> > + int result = -EINVAL;
> > +
> > + switch (lid_event_type) {
> > + case ACPI_BUTTON_LID_EVENT_KEY:
> > + if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
> > + lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
> > + pr_info("Do not notify initial lid state\n");
> > + }
> > + break;
> > + case ACPI_BUTTON_LID_EVENT_SWITCH:
> > + if (!strncmp(val, "open", sizeof("open") - 1)) {
> > + lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
> > + pr_info("Notify initial lid state as open\n");
> > + } else if (!strncmp(val, "method", sizeof("method") - 1)) {
> > + lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
> > + pr_info("Notify initial lid state"
> > + " with _LID return value\n");
> > + } else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
> > + lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
> > + pr_info("Do not notify initial lid state\n");
> > + }
> > + break;
> > + }
> > return result;
> > }
> >
> > static int param_get_lid_init_state(char *buffer, struct kernel_param
> *kp)
> > {
> > - switch (lid_init_state) {
> > - case ACPI_BUTTON_LID_INIT_OPEN:
> > - return sprintf(buffer, "open");
> > - case ACPI_BUTTON_LID_INIT_METHOD:
> > - return sprintf(buffer, "method");
> > - case ACPI_BUTTON_LID_INIT_IGNORE:
> > + switch (lid_event_type) {
> > + case ACPI_BUTTON_LID_EVENT_KEY:
> > return sprintf(buffer, "ignore");
> > - default:
> > - return sprintf(buffer, "invalid");
> > + case ACPI_BUTTON_LID_EVENT_SWITCH:
> > + switch (lid_init_state) {
> > + case ACPI_BUTTON_LID_INIT_OPEN:
> > + return sprintf(buffer, "open");
> > + case ACPI_BUTTON_LID_INIT_METHOD:
> > + return sprintf(buffer, "method");
> > + case ACPI_BUTTON_LID_INIT_IGNORE:
> > + return sprintf(buffer, "ignore");
> > + }
> > + break;
> > }
> > - return 0;
> > + return sprintf(buffer, "invalid");
> > }
> >
> > module_param_call(lid_init_state,
> > @@ -511,4 +542,34 @@ module_param_call(lid_init_state,
> > NULL, 0644);
> > MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial
> state");
> >
> > +static int param_set_lid_event_type(const char *val, struct
> kernel_param *kp)
> > +{
> > + int result = -EINVAL;
> > +
> > + if (!strncmp(val, "key", sizeof("key") - 1)) {
> > + lid_event_type = ACPI_BUTTON_LID_EVENT_KEY;
> > + pr_info("Notify lid state using key event\n");
> > + } else if (!strncmp(val, "switch", sizeof("switch") - 1)) {
> > + lid_event_type = ACPI_BUTTON_LID_EVENT_SWITCH;
> > + pr_info("Notify lid state using switch event\n");
> > + }
> > + return result;
> > +}
> > +
> > +static int param_get_lid_event_type(char *buffer, struct kernel_param
> *kp)
> > +{
> > + switch (lid_event_type) {
> > + case ACPI_BUTTON_LID_EVENT_KEY:
> > + return sprintf(buffer, "key");
> > + case ACPI_BUTTON_LID_EVENT_SWITCH:
> > + return sprintf(buffer, "switch");
> > + }
> > + return sprintf(buffer, "invalid");
> > +}
> > +
> > +module_param_call(lid_event_type,
> > + param_set_lid_event_type, param_get_lid_event_type,
> > + NULL, 0644);
> > +MODULE_PARM_DESC(lid_event_type, "Event type for reporting LID
> state");
>
> I don't think this is a good solution to have a kernel parameter. I
> thought the final decision were to have userspace decide which event
> was valid, and so we just need to export and emit both of events.
[Lv Zheng]
OK.
>
> _If_ you export a kernel parameter, it makes sense to have a dmi
> blacklist to have a good default experience, which is what you wanted
> to avoid.
[Lv Zheng]
I was thinking that the distribution vendors can configure a default boot parameters for a specific hardware.
> So if you just export and use both events at the same time, you will have:
> - correct ACPI machines will just have an extra KEY_LID_CLOSE event
> emitted, which will not harm logind
> - wrong ACPI machines will not have their SW_LID input event updated
> because it will be kept closed. But given that logind will ignore it,
> there is no harm either
[Lv Zheng]
I see.
>
> As Dmitry said, we could also have a KEY_LID_OPEN emitted for
> symmetrical purposes, but I am not entirely sure if this will confuse
> userspace or not. On the other hand, there are few users of these
> states, and we can teach them how to properly use them.
>
> So in the end, I think you should just get rid of the kernel
> parameter, export SW_LID, KEY_LID_CLOSE, KEY_LID_OPEN in the event
> node, and only add the KEY_LID_CLOSE|OPEN events on an actual acpi
> notification.
[Lv Zheng]
I'm sorry I didn't notice the KEY_LID_OPEN comment.
Thanks for the reminder.
>
> Then a small hwdb entry set will teach logind/powerd if they need to
> ignore the SW_LID event or not.
[Lv Zheng]
OK, I'll address what you've suggested in this email.
Thanks and best regards
-Lv
>
> Cheers,
> Benjamin
>
> > +
> > module_acpi_driver(acpi_button_driver);
> > diff --git a/include/uapi/linux/input-event-codes.h
> b/include/uapi/linux/input-event-codes.h
> > index 737fa32..df7c0c0 100644
> > --- a/include/uapi/linux/input-event-codes.h
> > +++ b/include/uapi/linux/input-event-codes.h
> > @@ -641,6 +641,12 @@
> > * e.g. teletext or data broadcast application (MHEG, MHP, HbbTV, etc.)
> > */
> > #define KEY_DATA 0x275
> > +/*
> > + * Special event sent by the lid drivers. The drivers may not be able to
> > + * issue "open" event, in which case, they send KEY_LID_CLOSE instead
> of
> > + * SW_LID.
> > + */
> > +#define KEY_LID_CLOSE 0x278
> >
> > #define BTN_TRIGGER_HAPPY 0x2c0
> > #define BTN_TRIGGER_HAPPY1 0x2c0
> > --
> > 1.7.10
> >
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