[PATCH v3 0/4] fujitsu_init() cleanup

[PATCH v3 0/4] fujitsu_init() cleanup

[Michał Kępień]

These patches should make fujitsu_init() a bit more palatable.  No
changes are made to platform device code yet, for clarity these will be
posted in a separate series after this one gets applied.

Changes from v2:

  - Patch 2/4 from v2 did not work as expected and was thus replaced
    with a rebased version of patch 3/4 from v1.

  - Added a check in patch 3/4 to prevent a NULL dereference when
    ACPI device FUJ02B1 is not present and ACPI device FUJ02E3 is.

Changes from v1:

  - Rebase on top of reworked Alan Jenkins' cleanup patch series.

  - Drop patch 1/4 from v1 as it has already been applied in reworked
    Alan Jenkins' cleanup patch series.

  - Patch 3/4 from v1 has been replaced with a completely different one
    (patch 2/4).  It needs to be tested on a relevant machine as it is
    based purely on a dump of a DSDT table (further details can be found
    in the patch itself).

  - Patch 3/4 in v2 is a rebased version of patch 8/10 from the reworked
    Alan Jenkins' cleanup patch series.  Patch 2/4 from v2 (the one
    mentioned in the previous bullet point) ensures this one can be
    safely applied without causing a NULL dereference under any
    circumstances.

 drivers/platform/x86/fujitsu-laptop.c | 98 ++++++++++++++++++-----------------
 1 file changed, 50 insertions(+), 48 deletions(-)

-- 
2.12.0

[PATCH v3 1/4] platform/x86: fujitsu-laptop: register backlight device in a separate function

[Michał Kępień]

Move code responsible for backlight device registration to a separate
function in order to simplify error handling and decrease indentation.
Simplify initialization of struct backlight_properties.  Use
KBUILD_MODNAME as device name to avoid repeating the same string literal
throughout the module.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
---
 drivers/platform/x86/fujitsu-laptop.c | 38 ++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index e12cc3504d48..185c929898d9 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -685,6 +685,25 @@ static const struct dmi_system_id fujitsu_dmi_table[] __initconst = {
 
 /* ACPI device for LCD brightness control */
 
+static int fujitsu_backlight_register(void)
+{
+	struct backlight_properties props = {
+		.brightness = fujitsu_bl->brightness_level,
+		.max_brightness = fujitsu_bl->max_brightness - 1,
+		.type = BACKLIGHT_PLATFORM
+	};
+	struct backlight_device *bd;
+
+	bd = backlight_device_register(KBUILD_MODNAME, NULL, NULL,
+				       &fujitsu_bl_ops, &props);
+	if (IS_ERR(bd))
+		return PTR_ERR(bd);
+
+	fujitsu_bl->bl_device = bd;
+
+	return 0;
+}
+
 static int acpi_fujitsu_bl_add(struct acpi_device *device)
 {
 	int state = 0;
@@ -1192,7 +1211,7 @@ MODULE_DEVICE_TABLE(acpi, fujitsu_ids);
 
 static int __init fujitsu_init(void)
 {
-	int ret, max_brightness;
+	int ret;
 
 	if (acpi_disabled)
 		return -ENODEV;
@@ -1232,22 +1251,9 @@ static int __init fujitsu_init(void)
 	/* Register backlight stuff */
 
 	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
-		struct backlight_properties props;
-
-		memset(&props, 0, sizeof(struct backlight_properties));
-		max_brightness = fujitsu_bl->max_brightness;
-		props.type = BACKLIGHT_PLATFORM;
-		props.max_brightness = max_brightness - 1;
-		fujitsu_bl->bl_device = backlight_device_register("fujitsu-laptop",
-								  NULL, NULL,
-								  &fujitsu_bl_ops,
-								  &props);
-		if (IS_ERR(fujitsu_bl->bl_device)) {
-			ret = PTR_ERR(fujitsu_bl->bl_device);
-			fujitsu_bl->bl_device = NULL;
+		ret = fujitsu_backlight_register();
+		if (ret)
 			goto fail_sysfs_group;
-		}
-		fujitsu_bl->bl_device->props.brightness = fujitsu_bl->brightness_level;
 	}
 
 	ret = platform_driver_register(&fujitsu_pf_driver);
-- 
2.12.0

[PATCH v3 2/4] platform/x86: fujitsu-laptop: sync backlight power status in acpi_fujitsu_laptop_add()

[Michał Kępień]

Registering an ACPI driver does not mean the device it handles has to
exist.  As the code which syncs backlight power status uses
call_fext_func(), it needs the FUJ02E3 ACPI device to be present, so
ensure that code is only run once the FUJ02E3 device is detected.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
---
 drivers/platform/x86/fujitsu-laptop.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index 185c929898d9..348af17cdc94 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -955,6 +955,14 @@ static int acpi_fujitsu_laptop_add(struct acpi_device *device)
 	/* Suspect this is a keymap of the application panel, print it */
 	pr_info("BTNI: [0x%x]\n", call_fext_func(FUNC_BUTTONS, 0x0, 0x0, 0x0));
 
+	/* Sync backlight power status */
+	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
+		if (call_fext_func(FUNC_BACKLIGHT, 0x2, 0x4, 0x0) == 3)
+			fujitsu_bl->bl_device->props.power = FB_BLANK_POWERDOWN;
+		else
+			fujitsu_bl->bl_device->props.power = FB_BLANK_UNBLANK;
+	}
+
 #if IS_ENABLED(CONFIG_LEDS_CLASS)
 	if (call_fext_func(FUNC_LEDS, 0x0, 0x0, 0x0) & LOGOLAMP_POWERON) {
 		result = led_classdev_register(&fujitsu_bl->pf_device->dev,
@@ -1272,14 +1280,6 @@ static int __init fujitsu_init(void)
 	if (ret)
 		goto fail_laptop1;
 
-	/* Sync backlight power status (needs FUJ02E3 device, hence deferred) */
-	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
-		if (call_fext_func(FUNC_BACKLIGHT, 0x2, 0x4, 0x0) == 3)
-			fujitsu_bl->bl_device->props.power = FB_BLANK_POWERDOWN;
-		else
-			fujitsu_bl->bl_device->props.power = FB_BLANK_UNBLANK;
-	}
-
 	pr_info("driver " FUJITSU_DRIVER_VERSION " successfully loaded\n");
 
 	return 0;
-- 
2.12.0

[PATCH v3 3/4] platform/x86: fujitsu-laptop: only register backlight device if FUJ02B1 is present

[Michał Kępień]

As the backlight device registered by fujitsu-laptop relies on the
FUJ02B1 ACPI device being present, only register the backlight device
once that ACPI device is detected.

Suggested-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
---
 drivers/platform/x86/fujitsu-laptop.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index 348af17cdc94..8b2701da4a4e 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -781,6 +781,12 @@ static int acpi_fujitsu_bl_add(struct acpi_device *device)
 		fujitsu_bl->max_brightness = FUJITSU_LCD_N_LEVELS;
 	get_lcd_level();
 
+	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
+		error = fujitsu_backlight_register();
+		if (error)
+			goto err_unregister_input_dev;
+	}
+
 	return 0;
 
 err_unregister_input_dev:
@@ -797,6 +803,7 @@ static int acpi_fujitsu_bl_remove(struct acpi_device *device)
 	struct fujitsu_bl *fujitsu_bl = acpi_driver_data(device);
 	struct input_dev *input = fujitsu_bl->input;
 
+	backlight_device_unregister(fujitsu_bl->bl_device);
 	input_unregister_device(input);
 
 	fujitsu_bl->acpi_handle = NULL;
@@ -956,7 +963,8 @@ static int acpi_fujitsu_laptop_add(struct acpi_device *device)
 	pr_info("BTNI: [0x%x]\n", call_fext_func(FUNC_BUTTONS, 0x0, 0x0, 0x0));
 
 	/* Sync backlight power status */
-	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
+	if (fujitsu_bl->bl_device &&
+	    acpi_video_get_backlight_type() == acpi_backlight_vendor) {
 		if (call_fext_func(FUNC_BACKLIGHT, 0x2, 0x4, 0x0) == 3)
 			fujitsu_bl->bl_device->props.power = FB_BLANK_POWERDOWN;
 		else
@@ -1256,17 +1264,9 @@ static int __init fujitsu_init(void)
 	if (ret)
 		goto fail_platform_device2;
 
-	/* Register backlight stuff */
-
-	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
-		ret = fujitsu_backlight_register();
-		if (ret)
-			goto fail_sysfs_group;
-	}
-
 	ret = platform_driver_register(&fujitsu_pf_driver);
 	if (ret)
-		goto fail_backlight;
+		goto fail_sysfs_group;
 
 	/* Register laptop driver */
 
@@ -1288,8 +1288,6 @@ static int __init fujitsu_init(void)
 	kfree(fujitsu_laptop);
 fail_laptop:
 	platform_driver_unregister(&fujitsu_pf_driver);
-fail_backlight:
-	backlight_device_unregister(fujitsu_bl->bl_device);
 fail_sysfs_group:
 	sysfs_remove_group(&fujitsu_bl->pf_device->dev.kobj,
 			   &fujitsu_pf_attribute_group);
@@ -1313,8 +1311,6 @@ static void __exit fujitsu_cleanup(void)
 
 	platform_driver_unregister(&fujitsu_pf_driver);
 
-	backlight_device_unregister(fujitsu_bl->bl_device);
-
 	sysfs_remove_group(&fujitsu_bl->pf_device->dev.kobj,
 			   &fujitsu_pf_attribute_group);
 
-- 
2.12.0

[PATCH v3 4/4] platform/x86: fujitsu-laptop: cleanup error labels in fujitsu_init()

[Michał Kępień]

Error labels currently used in fujitsu_init() are really hard to follow:
some (fail_laptop) indicate which operation has failed, others
(fail_sysfs_group) indicate where unrolling should start and the rest
(fail_platform_driver) is simply confusing.  Change them to follow the
pattern used throughout the rest of the module, i.e. make every label
indicate the first unrolling operation it leads to.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
---
 drivers/platform/x86/fujitsu-laptop.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index 8b2701da4a4e..5bd3f8f8e800 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -1244,60 +1244,60 @@ static int __init fujitsu_init(void)
 
 	ret = acpi_bus_register_driver(&acpi_fujitsu_bl_driver);
 	if (ret)
-		goto fail_acpi;
+		goto err_free_fujitsu_bl;
 
 	/* Register platform stuff */
 
 	fujitsu_bl->pf_device = platform_device_alloc("fujitsu-laptop", -1);
 	if (!fujitsu_bl->pf_device) {
 		ret = -ENOMEM;
-		goto fail_platform_driver;
+		goto err_unregister_acpi;
 	}
 
 	ret = platform_device_add(fujitsu_bl->pf_device);
 	if (ret)
-		goto fail_platform_device1;
+		goto err_put_platform_device;
 
 	ret =
 	    sysfs_create_group(&fujitsu_bl->pf_device->dev.kobj,
 			       &fujitsu_pf_attribute_group);
 	if (ret)
-		goto fail_platform_device2;
+		goto err_del_platform_device;
 
 	ret = platform_driver_register(&fujitsu_pf_driver);
 	if (ret)
-		goto fail_sysfs_group;
+		goto err_remove_sysfs_group;
 
 	/* Register laptop driver */
 
 	fujitsu_laptop = kzalloc(sizeof(struct fujitsu_laptop), GFP_KERNEL);
 	if (!fujitsu_laptop) {
 		ret = -ENOMEM;
-		goto fail_laptop;
+		goto err_unregister_platform_driver;
 	}
 
 	ret = acpi_bus_register_driver(&acpi_fujitsu_laptop_driver);
 	if (ret)
-		goto fail_laptop1;
+		goto err_free_fujitsu_laptop;
 
 	pr_info("driver " FUJITSU_DRIVER_VERSION " successfully loaded\n");
 
 	return 0;
 
-fail_laptop1:
+err_free_fujitsu_laptop:
 	kfree(fujitsu_laptop);
-fail_laptop:
+err_unregister_platform_driver:
 	platform_driver_unregister(&fujitsu_pf_driver);
-fail_sysfs_group:
+err_remove_sysfs_group:
 	sysfs_remove_group(&fujitsu_bl->pf_device->dev.kobj,
 			   &fujitsu_pf_attribute_group);
-fail_platform_device2:
+err_del_platform_device:
 	platform_device_del(fujitsu_bl->pf_device);
-fail_platform_device1:
+err_put_platform_device:
 	platform_device_put(fujitsu_bl->pf_device);
-fail_platform_driver:
+err_unregister_acpi:
 	acpi_bus_unregister_driver(&acpi_fujitsu_bl_driver);
-fail_acpi:
+err_free_fujitsu_bl:
 	kfree(fujitsu_bl);
 
 	return ret;
-- 
2.12.0

Re: [PATCH v3 0/4] fujitsu_init() cleanup

[Jonathan Woithe]

On Tue, Mar 07, 2017 at 11:15:12AM +0100, Micha?? K??pie?? wrote:
> These patches should make fujitsu_init() a bit more palatable.  No
> changes are made to platform device code yet, for clarity these will be
> posted in a separate series after this one gets applied.

I will test and review these as soon as possible.  It is likely to be later
this week or over the weekend.  I suspect this version will be good to go
but we should confirm this. :-)

Regards
  jonathan

Re: [PATCH v3 1/4] platform/x86: fujitsu-laptop: register backlight device in a separate function

[Michał Kępień]

> Move code responsible for backlight device registration to a separate
> function in order to simplify error handling and decrease indentation.
> Simplify initialization of struct backlight_properties.  Use
> KBUILD_MODNAME as device name to avoid repeating the same string literal
> throughout the module.
> 
> Signed-off-by: Michał Kępień <kernel@kempniu.pl>
> ---
>  drivers/platform/x86/fujitsu-laptop.c | 38 ++++++++++++++++++++---------------
>  1 file changed, 22 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
> index e12cc3504d48..185c929898d9 100644
> --- a/drivers/platform/x86/fujitsu-laptop.c
> +++ b/drivers/platform/x86/fujitsu-laptop.c
> @@ -685,6 +685,25 @@ static const struct dmi_system_id fujitsu_dmi_table[] __initconst = {
>  
>  /* ACPI device for LCD brightness control */
>  
> +static int fujitsu_backlight_register(void)
> +{
> +	struct backlight_properties props = {
> +		.brightness = fujitsu_bl->brightness_level,
> +		.max_brightness = fujitsu_bl->max_brightness - 1,
> +		.type = BACKLIGHT_PLATFORM
> +	};
> +	struct backlight_device *bd;
> +
> +	bd = backlight_device_register(KBUILD_MODNAME, NULL, NULL,
> +				       &fujitsu_bl_ops, &props);

I have only just now noticed that this effectively breaks userspace
interface as KBUILD_MODNAME is "fujitsu_laptop" while the previously
used device name was "fujitsu-laptop" (underscore vs. hyphen).

Jonathan, as this series is already long overdue, I suggest the
following course of action: please review these patches anyway and if
you find no other issues, please provide your Reviewed-by etc. as you
normally would.  Once you do that, I will post v4 which will use
"fujitsu-laptop" for backlight device name and will contain your v3
review tags.  Does that sound reasonable?

-- 
Best regards,
Michał Kępień

Re: [PATCH v3 0/4] fujitsu_init() cleanup

[Jonathan Woithe]

On Tue, Mar 07, 2017 at 11:15:12AM +0100, Micha?? K??pie?? wrote:
> These patches should make fujitsu_init() a bit more palatable.  No
> changes are made to platform device code yet, for clarity these will be
> posted in a separate series after this one gets applied.
> 
> Changes from v2:
> 
>   - Patch 2/4 from v2 did not work as expected and was thus replaced
>     with a rebased version of patch 3/4 from v1.
> 
>   - Added a check in patch 3/4 to prevent a NULL dereference when
>     ACPI device FUJ02B1 is not present and ACPI device FUJ02E3 is.
> 
> Changes from v1:
> 
>   - Rebase on top of reworked Alan Jenkins' cleanup patch series.
> 
>   - Drop patch 1/4 from v1 as it has already been applied in reworked
>     Alan Jenkins' cleanup patch series.
> 
>   - Patch 3/4 from v1 has been replaced with a completely different one
>     (patch 2/4).  It needs to be tested on a relevant machine as it is
>     based purely on a dump of a DSDT table (further details can be found
>     in the patch itself).
> 
>   - Patch 3/4 in v2 is a rebased version of patch 8/10 from the reworked
>     Alan Jenkins' cleanup patch series.  Patch 2/4 from v2 (the one
>     mentioned in the previous bullet point) ensures this one can be
>     safely applied without causing a NULL dereference under any
>     circumstances.
> 
>  drivers/platform/x86/fujitsu-laptop.c | 98 ++++++++++++++++++-----------------
>  1 file changed, 50 insertions(+), 48 deletions(-)

Having tested this V3 patch series on an S7020 I can confirm that there are
no key functional regressions with respect to the module components utilised
by this model: the bl_power and brightness controls work in the same way as
they have in the past.

My backlight control scripts failed because the attribute path they expected
(/sys/devices/virtual/backlight/fujitsu-laptop/) did not exist.  Instead
this patch creates /sys/devices/virtual/backlight/fujitsu_laptop/, the
difference being an underscore instead of a hyphen.  This API regression was
caused by the introduction of KBUILD_MODNAME to replace the literal
"fujitsu-laptop" in patch 1/4.  While it would be nice to use KBUILD_MODNAME
instead of the string literal, doing so does constitute a userspace API
breakage which is best avoided.  I therefore suggest KBUILD_MODNAME be
replaced with "fujitsu-laptop" in patch 1/4.

If the above substitution is made in patch 1/4 I am happy to see this series
applied.  It represents a further worthwhile improvement to the
fujitsu-laptop driver which will facilitate future maintenance and provide a
more consistent basis for upcoming improvements.

Tested-by: Jonathan Woithe <jwoithe@just42.net>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>

Regards
  jonathan

Re: [PATCH v3 1/4] platform/x86: fujitsu-laptop: register backlight device in a separate function

[Jonathan Woithe]

Hi Michael

On Fri, Mar 10, 2017 at 10:08:49AM +0100, Micha?? K??pie?? wrote:
> > Move code responsible for backlight device registration to a separate
> > function in order to simplify error handling and decrease indentation.
> > Simplify initialization of struct backlight_properties.  Use
> > KBUILD_MODNAME as device name to avoid repeating the same string literal
> > throughout the module.
> > 
> > Signed-off-by: Micha?? K??pie?? <kernel@kempniu.pl>
> > ---
> >  drivers/platform/x86/fujitsu-laptop.c | 38 ++++++++++++++++++++---------------
> >  1 file changed, 22 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
> > index e12cc3504d48..185c929898d9 100644
> > --- a/drivers/platform/x86/fujitsu-laptop.c
> > +++ b/drivers/platform/x86/fujitsu-laptop.c
> > @@ -685,6 +685,25 @@ static const struct dmi_system_id fujitsu_dmi_table[] __initconst = {
> >  
> >  /* ACPI device for LCD brightness control */
> >  
> > +static int fujitsu_backlight_register(void)
> > +{
> > +	struct backlight_properties props = {
> > +		.brightness = fujitsu_bl->brightness_level,
> > +		.max_brightness = fujitsu_bl->max_brightness - 1,
> > +		.type = BACKLIGHT_PLATFORM
> > +	};
> > +	struct backlight_device *bd;
> > +
> > +	bd = backlight_device_register(KBUILD_MODNAME, NULL, NULL,
> > +				       &fujitsu_bl_ops, &props);
> 
> I have only just now noticed that this effectively breaks userspace
> interface as KBUILD_MODNAME is "fujitsu_laptop" while the previously
> used device name was "fujitsu-laptop" (underscore vs. hyphen).

Ah yes, I noticed that too, as you see from the review I just sent through. 
Sorry, I didn't see the above post until after I'd sent the review in.  It's
no big deal though.

> Jonathan, as this series is already long overdue, I suggest the
> following course of action: please review these patches anyway and if
> you find no other issues, please provide your Reviewed-by etc. as you
> normally would.  Once you do that, I will post v4 which will use
> "fujitsu-laptop" for backlight device name and will contain your v3
> review tags.  Does that sound reasonable?

As per my review comments, I am happy with the patch series so long as the
backlight device name reverts to "fujitsu-laptop".  Your suggested course of
action sounds fine to me.  Alternatively, I could quickly and easily add
tags to a v4 post if that is seen to be more appropriate by Darren/Andy. 
I'm easy either way.

Regards
  jonathan

Re: [PATCH v3 1/4] platform/x86: fujitsu-laptop: register backlight device in a separate function

[Michał Kępień]

> Hi Michael
> 
> On Fri, Mar 10, 2017 at 10:08:49AM +0100, Micha?? K??pie?? wrote:
> > > Move code responsible for backlight device registration to a separate
> > > function in order to simplify error handling and decrease indentation.
> > > Simplify initialization of struct backlight_properties.  Use
> > > KBUILD_MODNAME as device name to avoid repeating the same string literal
> > > throughout the module.
> > > 
> > > Signed-off-by: Micha?? K??pie?? <kernel@kempniu.pl>
> > > ---
> > >  drivers/platform/x86/fujitsu-laptop.c | 38 ++++++++++++++++++++---------------
> > >  1 file changed, 22 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
> > > index e12cc3504d48..185c929898d9 100644
> > > --- a/drivers/platform/x86/fujitsu-laptop.c
> > > +++ b/drivers/platform/x86/fujitsu-laptop.c
> > > @@ -685,6 +685,25 @@ static const struct dmi_system_id fujitsu_dmi_table[] __initconst = {
> > >  
> > >  /* ACPI device for LCD brightness control */
> > >  
> > > +static int fujitsu_backlight_register(void)
> > > +{
> > > +	struct backlight_properties props = {
> > > +		.brightness = fujitsu_bl->brightness_level,
> > > +		.max_brightness = fujitsu_bl->max_brightness - 1,
> > > +		.type = BACKLIGHT_PLATFORM
> > > +	};
> > > +	struct backlight_device *bd;
> > > +
> > > +	bd = backlight_device_register(KBUILD_MODNAME, NULL, NULL,
> > > +				       &fujitsu_bl_ops, &props);
> > 
> > I have only just now noticed that this effectively breaks userspace
> > interface as KBUILD_MODNAME is "fujitsu_laptop" while the previously
> > used device name was "fujitsu-laptop" (underscore vs. hyphen).
> 
> Ah yes, I noticed that too, as you see from the review I just sent through. 
> Sorry, I didn't see the above post until after I'd sent the review in.  It's
> no big deal though.
> 
> > Jonathan, as this series is already long overdue, I suggest the
> > following course of action: please review these patches anyway and if
> > you find no other issues, please provide your Reviewed-by etc. as you
> > normally would.  Once you do that, I will post v4 which will use
> > "fujitsu-laptop" for backlight device name and will contain your v3
> > review tags.  Does that sound reasonable?
> 
> As per my review comments, I am happy with the patch series so long as the
> backlight device name reverts to "fujitsu-laptop".  Your suggested course of
> action sounds fine to me.  Alternatively, I could quickly and easily add
> tags to a v4 post if that is seen to be more appropriate by Darren/Andy. 
> I'm easy either way.

Sure, we can do it this way as well.  I will post v4 shortly.

-- 
Best regards,
Michał Kępień