[PATCH v13 4/4] battery: Add the ThinkPad "Not Charging" quirk

[PATCH v13 4/4] battery: Add the ThinkPad "Not Charging" quirk

[Ognjen Galic]

The EC/ACPI firmware on Lenovo ThinkPads used to report a status
of "Unknown" when the battery is between the charge start and
charge stop thresholds. On Windows, it reports "Not Charging"
so the quirk has been added to also report correctly.

Now the "status" attribute returns "Not Charging" when the
battery on ThinkPads is not physicaly charging.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ognjen Galic <smclt30p@gmail.com>
---

Notes:
    v7:
    * Added all the style changes as suggested by Rafael
    * Re-ordered the series to make this a post-implement
    bugfix
    
    v8:
    * No changes in this patch in v8
    
    v9:
    * No changes in this patch in v9
    
    v10:
    * No changes in this patch in v10
    
    v11:
    * Fix formatting of changelog
    
    v12:
    * No changes in this patch in v12
    
    v13:
    * No changes in this patch in v13

 drivers/acpi/battery.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 3fab2cb9e..e4b23738c 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -74,6 +74,7 @@ static async_cookie_t async_cookie;
 static bool battery_driver_registered;
 static int battery_bix_broken_package;
 static int battery_notification_delay_ms;
+static int battery_quirk_notcharging;
 static int battery_full_discharging;
 static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
@@ -229,6 +230,8 @@ static int acpi_battery_get_property(struct power_supply *psy,
 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
 		else if (acpi_battery_is_charged(battery))
 			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else if (battery_quirk_notcharging)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 		else
 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
 		break;
@@ -707,7 +710,7 @@ EXPORT_SYMBOL_GPL(battery_hook_register);
  * This function gets called right after the battery sysfs
  * attributes have been added, so that the drivers that
  * define custom sysfs attributes can add their own.
-*/
+ */
 static void battery_hook_add_battery(struct acpi_battery *battery)
 {
 	struct acpi_battery_hook *hook_node;
@@ -1315,6 +1318,12 @@ static int __init battery_full_discharging_quirk(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int __init battery_quirk_not_charging(const struct dmi_system_id *d)
+{
+	battery_quirk_notcharging = 1;
+	return 0;
+}
+
 static const struct dmi_system_id bat_dmi_table[] __initconst = {
 	{
 		.callback = battery_bix_broken_package_quirk,
@@ -1348,6 +1357,19 @@ static const struct dmi_system_id bat_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "UX305LA"),
 		},
 	},
+	{
+		/*
+		 * On Lenovo ThinkPads the BIOS specification defines
+		 * a state when the bits for charging and discharging
+		 * are both set to 0. That state is "Not Charging".
+		 */
+		.callback = battery_quirk_not_charging,
+		.ident = "Lenovo ThinkPad",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad"),
+		},
+	},
 	{},
 };
 
-- 
2.14.1

Re: [PATCH v13 4/4] battery: Add the ThinkPad "Not Charging" quirk

[Henrique de Moraes Holschuh]

On Wed, 07 Feb 2018, Ognjen Galic wrote:
> The EC/ACPI firmware on Lenovo ThinkPads used to report a status
> of "Unknown" when the battery is between the charge start and
> charge stop thresholds. On Windows, it reports "Not Charging"
> so the quirk has been added to also report correctly.
> 
> Now the "status" attribute returns "Not Charging" when the
> battery on ThinkPads is not physicaly charging.
> 
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Ognjen Galic <smclt30p@gmail.com>

AFAIK, This behavior goes back to the initial SBS implementation in the
IBM era ECs of the Thinkpads...  We've always called it "idle" in the
linux-thinkpad community.  The behavior comes from SBS
(http://smartbattery.org/specs/), the EC was reporting its status
(charging/not charging *THIS* battery) in one bit, and the battery's
status (discharging/not discharging *THIS* battery) in a different bit.

It was rather simple to observe the behavior of those bits in a
two-battery system.

Would that apply to these newer Lenovo models?  If so, you might want to
consider using "idle", instead. "not charging" does _not_ imply "neither
charging nor discharging", while "idle" does.

-- 
  Henrique Holschuh

Re: [PATCH v13 4/4] battery: Add the ThinkPad "Not Charging" quirk

[Sebastian Reichel]

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Hi,

On Fri, Feb 09, 2018 at 08:45:30AM -0200, Henrique de Moraes Holschuh wrote:
> On Wed, 07 Feb 2018, Ognjen Galic wrote:
> > The EC/ACPI firmware on Lenovo ThinkPads used to report a status
> > of "Unknown" when the battery is between the charge start and
> > charge stop thresholds. On Windows, it reports "Not Charging"
> > so the quirk has been added to also report correctly.
> > 
> > Now the "status" attribute returns "Not Charging" when the
> > battery on ThinkPads is not physicaly charging.
> > 
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > Signed-off-by: Ognjen Galic <smclt30p@gmail.com>
> 
> AFAIK, This behavior goes back to the initial SBS implementation in the
> IBM era ECs of the Thinkpads...  We've always called it "idle" in the
> linux-thinkpad community.  The behavior comes from SBS
> (http://smartbattery.org/specs/), the EC was reporting its status
> (charging/not charging *THIS* battery) in one bit, and the battery's
> status (discharging/not discharging *THIS* battery) in a different bit.
> 
> It was rather simple to observe the behavior of those bits in a
> two-battery system.
> 
> Would that apply to these newer Lenovo models?  If so, you might want to
> consider using "idle", instead. "not charging" does _not_ imply "neither
> charging nor discharging", while "idle" does.

I agree, that "Idle" is a better term than "Not Charging", but
the power supply property exists with this name since it has
been introduced. This is exposed to userspace and cannot be
changed easily.

-- Sebastian

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Re: [PATCH v13 4/4] battery: Add the ThinkPad "Not Charging" quirk

[Ognjen Galić]

On Fri, Feb 09, 2018 at 02:26:41PM +0100, Sebastian Reichel wrote:
> Hi,
> 
> On Fri, Feb 09, 2018 at 08:45:30AM -0200, Henrique de Moraes Holschuh wrote:
> > On Wed, 07 Feb 2018, Ognjen Galic wrote:
> > > The EC/ACPI firmware on Lenovo ThinkPads used to report a status
> > > of "Unknown" when the battery is between the charge start and
> > > charge stop thresholds. On Windows, it reports "Not Charging"
> > > so the quirk has been added to also report correctly.
> > > 
> > > Now the "status" attribute returns "Not Charging" when the
> > > battery on ThinkPads is not physicaly charging.
> > > 
> > > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > > Signed-off-by: Ognjen Galic <smclt30p@gmail.com>
> > 
> > AFAIK, This behavior goes back to the initial SBS implementation in the
> > IBM era ECs of the Thinkpads...  We've always called it "idle" in the
> > linux-thinkpad community.  The behavior comes from SBS
> > (http://smartbattery.org/specs/), the EC was reporting its status
> > (charging/not charging *THIS* battery) in one bit, and the battery's
> > status (discharging/not discharging *THIS* battery) in a different bit.
> > 
> > It was rather simple to observe the behavior of those bits in a
> > two-battery system.
> > 
> > Would that apply to these newer Lenovo models?  If so, you might want to
> > consider using "idle", instead. "not charging" does _not_ imply "neither
> > charging nor discharging", while "idle" does.
> 
> I agree, that "Idle" is a better term than "Not Charging", but
> the power supply property exists with this name since it has
> been introduced. This is exposed to userspace and cannot be
> changed easily.

I agree. There is no need to add new definitions to the generic 
power supply API for "Idle", as basically "Not Charging" can also
describe that condition. That's what Microsoft Windows does, since XP.

> 
> -- Sebastian