* [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON
@ 2012-12-04 5:28 Jingoo Han
2012-12-04 22:58 ` Andrew Morton
2012-12-04 23:27 ` Marko Katić
0 siblings, 2 replies; 5+ messages in thread
From: Jingoo Han @ 2012-12-04 5:28 UTC (permalink / raw)
To: 'Andrew Morton', 'LKML'
Cc: 'Marko Katic', 'Grant Likely',
'Florian Tobias Schandinat', 'Richard Purdie',
linux-arm-kernel, 'Jingoo Han'
From: Marko Katic <dromede@gmail.com>
Changing backlight intensity on an Akita (Sharp Zaurus C-1000)
triggers WARN_ON message:
WARNING: at drivers/gpio/gpiolib.c:1672 __gpio_set_value+0x38/0xa4()
Modules linked in:
Backtrace:
[<c000c0ac>] (dump_backtrace+0x0/0x110) from [<c02c8278>] (dump_stack+0x18/0x1c)
r6:c0158fc8 r5:00000009 r4:00000000 r3:c03d4f70
[<c02c8260>] (dump_stack+0x0/0x1c) from [<c0019194>] (warn_slowpath_common+0x54/0x6c)
[<c0019140>] (warn_slowpath_common+0x0/0x6c) from [<c00191d0>] (warn_slowpath_null+0x24/0x2c)
r8:c38d5c00 r7:c03f82c0 r6:00000000 r5:000000d0 r4:c384e4fc
r3:00000009
[<c00191ac>] (warn_slowpath_null+0x0/0x2c) from [<c0158fc8>] (__gpio_set_value+0x38/0xa4)
[<c0158f90>] (__gpio_set_value+0x0/0xa4) from [<c0169b4c>] (corgi_bl_set_intensity+0x44/0x74)
r7:c3933418 r6:c3933400 r5:c392cdf0 r4:0000002f
[<c0169b08>] (corgi_bl_set_intensity+0x0/0x74) from [<c0169c1c>] (corgi_bl_update_status+0x5c/0x64)
r5:c03d31f0 r4:c3933400
[<c0169bc0>] (corgi_bl_update_status+0x0/0x64) from [<c02c3a68>] (corgi_lcd_probe+0x1a8/0x258)
r4:c392cdf0 r3:c0169bc0
[<c02c38c0>] (corgi_lcd_probe+0x0/0x258) from [<c01da7a4>] (spi_drv_probe+0x20/0x24)
r8:00000052 r7:c0192d9c r6:c03da6e8 r5:c38d5c34 r4:c38d5c00
[<c01da784>] (spi_drv_probe+0x0/0x24) from [<c0192c44>] (driver_probe_device+0xb0/0x208)
[<c0192b94>] (driver_probe_device+0x0/0x208) from [<c0192e0c>] (__driver_attach+0x70/0x94)
r6:c03da6e8 r5:c38d5c34 r4:c38d5c00 r3:00000000
[<c0192d9c>] (__driver_attach+0x0/0x94) from [<c0191268>] (bus_for_each_dev+0x54/0x90)
r6:c03da6e8 r5:c3827e80 r4:00000000 r3:00000000
[<c0191214>] (bus_for_each_dev+0x0/0x90) from [<c01927a4>] (driver_attach+0x20/0x28)
r7:00000000 r6:c03e29ec r5:c3932980 r4:c03da6e8
[<c0192784>] (driver_attach+0x0/0x28) from [<c0192340>] (bus_add_driver+0xd4/0x22c)
[<c019226c>] (bus_add_driver+0x0/0x22c) from [<c019335c>] (driver_register+0xa4/0x134)
r8:00000052 r7:c03ea900 r6:c03c32ac r5:c03bdfc8 r4:c03da6e8
[<c01932b8>] (driver_register+0x0/0x134) from [<c01db7ec>] (spi_register_driver+0x4c/0x60)
[<c01db7a0>] (spi_register_driver+0x0/0x60) from [<c03b3ce0>] (corgi_lcd_driver_init+0x14/0x1c)
[<c03b3ccc>] (corgi_lcd_driver_init+0x0/0x1c) from [<c000868c>] (do_one_initcall+0x9c/0x174)
[<c00085f0>] (do_one_initcall+0x0/0x174) from [<c02c1b94>] (kernel_init+0xf4/0x2a8)
[<c02c1aa0>] (kernel_init+0x0/0x2a8) from [<c0009270>] (ret_from_fork+0x14/0x24)
---[ end trace a863a63f242ee38c ]---
Akita machines have backlight controls hooked to a gpio expander chip,
max7310. In this case, pca953x_gpio_set_value() can be called to control
gpio, and pca953x_setup_gpio() sets can_sleep flag. Therefore,
gpio_set_value_cansleep() should be used in order to avoid WARN_ON on
akita machines.
Akita is the only exception in this case since other users of corgi_lcd
access backlight gpio controls through a different gpio expander such as
max7310 which does not set the can_sleep flag.
[jg1.han@samsung.com: used gpio_cansleep()]
Signed-off-by: Marko Katic <dromede@gmail.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
---
drivers/video/backlight/corgi_lcd.c | 17 +++++++++++++----
1 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c
index e2e1b62..e5168f4 100644
--- a/drivers/video/backlight/corgi_lcd.c
+++ b/drivers/video/backlight/corgi_lcd.c
@@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity)
/* Bit 5 via GPIO_BACKLIGHT_CONT */
cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted;
- if (gpio_is_valid(lcd->gpio_backlight_cont))
- gpio_set_value(lcd->gpio_backlight_cont, cont);
+ if (gpio_is_valid(lcd->gpio_backlight_cont)) {
+ if (gpio_cansleep(lcd->gpio_backlight_cont))
+ gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont);
+ else
+ gpio_set_value(lcd->gpio_backlight_cont, cont);
+ }
- if (gpio_is_valid(lcd->gpio_backlight_on))
- gpio_set_value(lcd->gpio_backlight_on, intensity);
+ if (gpio_is_valid(lcd->gpio_backlight_on)) {
+ if (gpio_cansleep(lcd->gpio_backlight_on))
+ gpio_set_value_cansleep(lcd->gpio_backlight_on,
+ intensity);
+ else
+ gpio_set_value(lcd->gpio_backlight_on, intensity);
+ }
if (lcd->kick_battery)
lcd->kick_battery();
--
1.7.2.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON
2012-12-04 5:28 [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON Jingoo Han
@ 2012-12-04 22:58 ` Andrew Morton
2012-12-05 1:17 ` Jingoo Han
2012-12-04 23:27 ` Marko Katić
1 sibling, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2012-12-04 22:58 UTC (permalink / raw)
To: Jingoo Han
Cc: 'LKML', 'Marko Katic', 'Grant Likely',
'Florian Tobias Schandinat', 'Richard Purdie',
linux-arm-kernel
On Tue, 04 Dec 2012 14:28:15 +0900
Jingoo Han <jg1.han@samsung.com> wrote:
> From: Marko Katic <dromede@gmail.com>
>
> Changing backlight intensity on an Akita (Sharp Zaurus C-1000)
> triggers WARN_ON message:
Well, I queued it up.
> ...
>
> --- a/drivers/video/backlight/corgi_lcd.c
> +++ b/drivers/video/backlight/corgi_lcd.c
> @@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity)
> /* Bit 5 via GPIO_BACKLIGHT_CONT */
> cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted;
>
> - if (gpio_is_valid(lcd->gpio_backlight_cont))
> - gpio_set_value(lcd->gpio_backlight_cont, cont);
> + if (gpio_is_valid(lcd->gpio_backlight_cont)) {
> + if (gpio_cansleep(lcd->gpio_backlight_cont))
> + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont);
> + else
> + gpio_set_value(lcd->gpio_backlight_cont, cont);
> + }
But this looks utterly daft. Grant, these two things are the same - do
we need both of them?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON
2012-12-04 5:28 [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON Jingoo Han
2012-12-04 22:58 ` Andrew Morton
@ 2012-12-04 23:27 ` Marko Katić
2012-12-05 0:29 ` Jingoo Han
1 sibling, 1 reply; 5+ messages in thread
From: Marko Katić @ 2012-12-04 23:27 UTC (permalink / raw)
To: Jingoo Han
Cc: Andrew Morton, LKML, Grant Likely, Florian Tobias Schandinat,
Richard Purdie, linux-arm-kernel
On Tue, Dec 4, 2012 at 6:28 AM, Jingoo Han <jg1.han@samsung.com> wrote:
> From: Marko Katic <dromede@gmail.com>
>
> Changing backlight intensity on an Akita (Sharp Zaurus C-1000)
> triggers WARN_ON message:
>
> WARNING: at drivers/gpio/gpiolib.c:1672 __gpio_set_value+0x38/0xa4()
> Modules linked in:
> Backtrace:
> [<c000c0ac>] (dump_backtrace+0x0/0x110) from [<c02c8278>] (dump_stack+0x18/0x1c)
> r6:c0158fc8 r5:00000009 r4:00000000 r3:c03d4f70
> [<c02c8260>] (dump_stack+0x0/0x1c) from [<c0019194>] (warn_slowpath_common+0x54/0x6c)
> [<c0019140>] (warn_slowpath_common+0x0/0x6c) from [<c00191d0>] (warn_slowpath_null+0x24/0x2c)
> r8:c38d5c00 r7:c03f82c0 r6:00000000 r5:000000d0 r4:c384e4fc
> r3:00000009
> [<c00191ac>] (warn_slowpath_null+0x0/0x2c) from [<c0158fc8>] (__gpio_set_value+0x38/0xa4)
> [<c0158f90>] (__gpio_set_value+0x0/0xa4) from [<c0169b4c>] (corgi_bl_set_intensity+0x44/0x74)
> r7:c3933418 r6:c3933400 r5:c392cdf0 r4:0000002f
> [<c0169b08>] (corgi_bl_set_intensity+0x0/0x74) from [<c0169c1c>] (corgi_bl_update_status+0x5c/0x64)
> r5:c03d31f0 r4:c3933400
> [<c0169bc0>] (corgi_bl_update_status+0x0/0x64) from [<c02c3a68>] (corgi_lcd_probe+0x1a8/0x258)
> r4:c392cdf0 r3:c0169bc0
> [<c02c38c0>] (corgi_lcd_probe+0x0/0x258) from [<c01da7a4>] (spi_drv_probe+0x20/0x24)
> r8:00000052 r7:c0192d9c r6:c03da6e8 r5:c38d5c34 r4:c38d5c00
> [<c01da784>] (spi_drv_probe+0x0/0x24) from [<c0192c44>] (driver_probe_device+0xb0/0x208)
> [<c0192b94>] (driver_probe_device+0x0/0x208) from [<c0192e0c>] (__driver_attach+0x70/0x94)
> r6:c03da6e8 r5:c38d5c34 r4:c38d5c00 r3:00000000
> [<c0192d9c>] (__driver_attach+0x0/0x94) from [<c0191268>] (bus_for_each_dev+0x54/0x90)
> r6:c03da6e8 r5:c3827e80 r4:00000000 r3:00000000
> [<c0191214>] (bus_for_each_dev+0x0/0x90) from [<c01927a4>] (driver_attach+0x20/0x28)
> r7:00000000 r6:c03e29ec r5:c3932980 r4:c03da6e8
> [<c0192784>] (driver_attach+0x0/0x28) from [<c0192340>] (bus_add_driver+0xd4/0x22c)
> [<c019226c>] (bus_add_driver+0x0/0x22c) from [<c019335c>] (driver_register+0xa4/0x134)
> r8:00000052 r7:c03ea900 r6:c03c32ac r5:c03bdfc8 r4:c03da6e8
> [<c01932b8>] (driver_register+0x0/0x134) from [<c01db7ec>] (spi_register_driver+0x4c/0x60)
> [<c01db7a0>] (spi_register_driver+0x0/0x60) from [<c03b3ce0>] (corgi_lcd_driver_init+0x14/0x1c)
> [<c03b3ccc>] (corgi_lcd_driver_init+0x0/0x1c) from [<c000868c>] (do_one_initcall+0x9c/0x174)
> [<c00085f0>] (do_one_initcall+0x0/0x174) from [<c02c1b94>] (kernel_init+0xf4/0x2a8)
> [<c02c1aa0>] (kernel_init+0x0/0x2a8) from [<c0009270>] (ret_from_fork+0x14/0x24)
> ---[ end trace a863a63f242ee38c ]---
>
> Akita machines have backlight controls hooked to a gpio expander chip,
> max7310. In this case, pca953x_gpio_set_value() can be called to control
> gpio, and pca953x_setup_gpio() sets can_sleep flag. Therefore,
> gpio_set_value_cansleep() should be used in order to avoid WARN_ON on
> akita machines.
>
> Akita is the only exception in this case since other users of corgi_lcd
> access backlight gpio controls through a different gpio expander such as
> max7310 which does not set the can_sleep flag.
I think you forgot to delete "such as max7310". Akita has
the max7310, all the other models have a different expander.
>
> [jg1.han@samsung.com: used gpio_cansleep()]
> Signed-off-by: Marko Katic <dromede@gmail.com>
> Signed-off-by: Jingoo Han <jg1.han@samsung.com>
> ---
> drivers/video/backlight/corgi_lcd.c | 17 +++++++++++++----
> 1 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c
> index e2e1b62..e5168f4 100644
> --- a/drivers/video/backlight/corgi_lcd.c
> +++ b/drivers/video/backlight/corgi_lcd.c
> @@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity)
> /* Bit 5 via GPIO_BACKLIGHT_CONT */
> cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted;
>
> - if (gpio_is_valid(lcd->gpio_backlight_cont))
> - gpio_set_value(lcd->gpio_backlight_cont, cont);
> + if (gpio_is_valid(lcd->gpio_backlight_cont)) {
> + if (gpio_cansleep(lcd->gpio_backlight_cont))
> + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont);
> + else
> + gpio_set_value(lcd->gpio_backlight_cont, cont);
> + }
>
> - if (gpio_is_valid(lcd->gpio_backlight_on))
> - gpio_set_value(lcd->gpio_backlight_on, intensity);
> + if (gpio_is_valid(lcd->gpio_backlight_on)) {
> + if (gpio_cansleep(lcd->gpio_backlight_on))
> + gpio_set_value_cansleep(lcd->gpio_backlight_on,
> + intensity);
> + else
> + gpio_set_value(lcd->gpio_backlight_on, intensity);
> + }
>
> if (lcd->kick_battery)
> lcd->kick_battery();
> --
> 1.7.2.5
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON
2012-12-04 23:27 ` Marko Katić
@ 2012-12-05 0:29 ` Jingoo Han
0 siblings, 0 replies; 5+ messages in thread
From: Jingoo Han @ 2012-12-05 0:29 UTC (permalink / raw)
To: 'Marko Katić'
Cc: 'Andrew Morton', 'LKML', 'Grant Likely',
'Florian Tobias Schandinat', 'Richard Purdie',
linux-arm-kernel, 'Jingoo Han'
On Wednesday, December 05, 2012 8:28 AM, Marko Katic wrote
> On Tue, Dec 4, 2012 at 6:28 AM, Jingoo Han <jg1.han@samsung.com> wrote:
> > From: Marko Katic <dromede@gmail.com>
> >
> > Changing backlight intensity on an Akita (Sharp Zaurus C-1000)
> > triggers WARN_ON message:
> >
> > WARNING: at drivers/gpio/gpiolib.c:1672 __gpio_set_value+0x38/0xa4()
> > Modules linked in:
> > Backtrace:
> > [<c000c0ac>] (dump_backtrace+0x0/0x110) from [<c02c8278>] (dump_stack+0x18/0x1c)
> > r6:c0158fc8 r5:00000009 r4:00000000 r3:c03d4f70
> > [<c02c8260>] (dump_stack+0x0/0x1c) from [<c0019194>] (warn_slowpath_common+0x54/0x6c)
> > [<c0019140>] (warn_slowpath_common+0x0/0x6c) from [<c00191d0>] (warn_slowpath_null+0x24/0x2c)
> > r8:c38d5c00 r7:c03f82c0 r6:00000000 r5:000000d0 r4:c384e4fc
> > r3:00000009
> > [<c00191ac>] (warn_slowpath_null+0x0/0x2c) from [<c0158fc8>] (__gpio_set_value+0x38/0xa4)
> > [<c0158f90>] (__gpio_set_value+0x0/0xa4) from [<c0169b4c>] (corgi_bl_set_intensity+0x44/0x74)
> > r7:c3933418 r6:c3933400 r5:c392cdf0 r4:0000002f
> > [<c0169b08>] (corgi_bl_set_intensity+0x0/0x74) from [<c0169c1c>] (corgi_bl_update_status+0x5c/0x64)
> > r5:c03d31f0 r4:c3933400
> > [<c0169bc0>] (corgi_bl_update_status+0x0/0x64) from [<c02c3a68>] (corgi_lcd_probe+0x1a8/0x258)
> > r4:c392cdf0 r3:c0169bc0
> > [<c02c38c0>] (corgi_lcd_probe+0x0/0x258) from [<c01da7a4>] (spi_drv_probe+0x20/0x24)
> > r8:00000052 r7:c0192d9c r6:c03da6e8 r5:c38d5c34 r4:c38d5c00
> > [<c01da784>] (spi_drv_probe+0x0/0x24) from [<c0192c44>] (driver_probe_device+0xb0/0x208)
> > [<c0192b94>] (driver_probe_device+0x0/0x208) from [<c0192e0c>] (__driver_attach+0x70/0x94)
> > r6:c03da6e8 r5:c38d5c34 r4:c38d5c00 r3:00000000
> > [<c0192d9c>] (__driver_attach+0x0/0x94) from [<c0191268>] (bus_for_each_dev+0x54/0x90)
> > r6:c03da6e8 r5:c3827e80 r4:00000000 r3:00000000
> > [<c0191214>] (bus_for_each_dev+0x0/0x90) from [<c01927a4>] (driver_attach+0x20/0x28)
> > r7:00000000 r6:c03e29ec r5:c3932980 r4:c03da6e8
> > [<c0192784>] (driver_attach+0x0/0x28) from [<c0192340>] (bus_add_driver+0xd4/0x22c)
> > [<c019226c>] (bus_add_driver+0x0/0x22c) from [<c019335c>] (driver_register+0xa4/0x134)
> > r8:00000052 r7:c03ea900 r6:c03c32ac r5:c03bdfc8 r4:c03da6e8
> > [<c01932b8>] (driver_register+0x0/0x134) from [<c01db7ec>] (spi_register_driver+0x4c/0x60)
> > [<c01db7a0>] (spi_register_driver+0x0/0x60) from [<c03b3ce0>] (corgi_lcd_driver_init+0x14/0x1c)
> > [<c03b3ccc>] (corgi_lcd_driver_init+0x0/0x1c) from [<c000868c>] (do_one_initcall+0x9c/0x174)
> > [<c00085f0>] (do_one_initcall+0x0/0x174) from [<c02c1b94>] (kernel_init+0xf4/0x2a8)
> > [<c02c1aa0>] (kernel_init+0x0/0x2a8) from [<c0009270>] (ret_from_fork+0x14/0x24)
> > ---[ end trace a863a63f242ee38c ]---
> >
> > Akita machines have backlight controls hooked to a gpio expander chip,
> > max7310. In this case, pca953x_gpio_set_value() can be called to control
> > gpio, and pca953x_setup_gpio() sets can_sleep flag. Therefore,
> > gpio_set_value_cansleep() should be used in order to avoid WARN_ON on
> > akita machines.
> >
> > Akita is the only exception in this case since other users of corgi_lcd
> > access backlight gpio controls through a different gpio expander such as
> > max7310 which does not set the can_sleep flag.
>
> I think you forgot to delete "such as max7310". Akita has
> the max7310, all the other models have a different expander.
Yes, you're right.
I added an unnecessary word, 'such as max7310'.
It should be deleted.
I will send v4 patch, soon.
Best regards,
Jingoo Han
>
> >
> > [jg1.han@samsung.com: used gpio_cansleep()]
> > Signed-off-by: Marko Katic <dromede@gmail.com>
> > Signed-off-by: Jingoo Han <jg1.han@samsung.com>
> > ---
> > drivers/video/backlight/corgi_lcd.c | 17 +++++++++++++----
> > 1 files changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c
> > index e2e1b62..e5168f4 100644
> > --- a/drivers/video/backlight/corgi_lcd.c
> > +++ b/drivers/video/backlight/corgi_lcd.c
> > @@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity)
> > /* Bit 5 via GPIO_BACKLIGHT_CONT */
> > cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted;
> >
> > - if (gpio_is_valid(lcd->gpio_backlight_cont))
> > - gpio_set_value(lcd->gpio_backlight_cont, cont);
> > + if (gpio_is_valid(lcd->gpio_backlight_cont)) {
> > + if (gpio_cansleep(lcd->gpio_backlight_cont))
> > + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont);
> > + else
> > + gpio_set_value(lcd->gpio_backlight_cont, cont);
> > + }
> >
> > - if (gpio_is_valid(lcd->gpio_backlight_on))
> > - gpio_set_value(lcd->gpio_backlight_on, intensity);
> > + if (gpio_is_valid(lcd->gpio_backlight_on)) {
> > + if (gpio_cansleep(lcd->gpio_backlight_on))
> > + gpio_set_value_cansleep(lcd->gpio_backlight_on,
> > + intensity);
> > + else
> > + gpio_set_value(lcd->gpio_backlight_on, intensity);
> > + }
> >
> > if (lcd->kick_battery)
> > lcd->kick_battery();
> > --
> > 1.7.2.5
> >
> >
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON
2012-12-04 22:58 ` Andrew Morton
@ 2012-12-05 1:17 ` Jingoo Han
0 siblings, 0 replies; 5+ messages in thread
From: Jingoo Han @ 2012-12-05 1:17 UTC (permalink / raw)
To: 'Andrew Morton'
Cc: 'LKML', 'Marko Katic', 'Grant Likely',
'Florian Tobias Schandinat', 'Richard Purdie',
linux-arm-kernel, 'Jingoo Han'
On Wednesday, December 05, 2012 7:58 AM, Andrew Morton wrote
> On Tue, 04 Dec 2012 14:28:15 +0900
> Jingoo Han <jg1.han@samsung.com> wrote:
>
> > From: Marko Katic <dromede@gmail.com>
> >
> > Changing backlight intensity on an Akita (Sharp Zaurus C-1000)
> > triggers WARN_ON message:
>
> Well, I queued it up.
>
> > ...
> >
> > --- a/drivers/video/backlight/corgi_lcd.c
> > +++ b/drivers/video/backlight/corgi_lcd.c
> > @@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity)
> > /* Bit 5 via GPIO_BACKLIGHT_CONT */
> > cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted;
> >
> > - if (gpio_is_valid(lcd->gpio_backlight_cont))
> > - gpio_set_value(lcd->gpio_backlight_cont, cont);
> > + if (gpio_is_valid(lcd->gpio_backlight_cont)) {
> > + if (gpio_cansleep(lcd->gpio_backlight_cont))
> > + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont);
> > + else
> > + gpio_set_value(lcd->gpio_backlight_cont, cont);
> > + }
>
> But this looks utterly daft. Grant, these two things are the same - do
> we need both of them?
Hi Andrew,
There is another difference, except for warning message.
There is might_sleep_if(extra_checks) in gpio_set_value_cansleep().
Also, I saw the Documentation/gpio.txt as below:
172 /* GPIO OUTPUT */
173 void gpio_set_value(unsigned gpio, int value);
...
213 /* GPIO OUTPUT, might sleep */
214 void gpio_set_value_cansleep(unsigned gpio, int value);
Best regards,
Jingoo Han
^ permalink raw reply [flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-12-04 5:28 [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON Jingoo Han
2012-12-04 22:58 ` Andrew Morton
2012-12-05 1:17 ` Jingoo Han
2012-12-04 23:27 ` Marko Katić
2012-12-05 0:29 ` Jingoo Han
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