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Message-id: <000301cdd362$34d9d800$9e8d8800$%han@samsung.com> Date: Thu, 06 Dec 2012 12:31:40 +0900 From: Jingoo Han <jg1.han@...sung.com> To: 'Andrew Morton' <akpm@...ux-foundation.org>, 'LKML' <linux-kernel@...r.kernel.org> Cc: 'Marko Katic' <dromede@...il.com>, 'Russell King - ARM Linux' <linux@....linux.org.uk>, 'Grant Likely' <grant.likely@...retlab.ca>, 'Florian Tobias Schandinat' <FlorianSchandinat@....de>, 'Richard Purdie' <rpurdie@...ys.net>, linux-arm-kernel@...ts.infradead.org, 'Jingoo Han' <jg1.han@...sung.com> Subject: [PATCH v5] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON From: Marko Katic <dromede@...il.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 using i2c transfers which can sleep. 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 which does not set the can_sleep flag. Signed-off-by: Marko Katic <dromede@...il.com> Signed-off-by: Jingoo Han <jg1.han@...sung.com> --- Change since v4: - use only gpio_set_value_cansleep() drivers/video/backlight/corgi_lcd.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c index e2e1b62..e323fcb 100644 --- a/drivers/video/backlight/corgi_lcd.c +++ b/drivers/video/backlight/corgi_lcd.c @@ -409,10 +409,10 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity) cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted; if (gpio_is_valid(lcd->gpio_backlight_cont)) - gpio_set_value(lcd->gpio_backlight_cont, cont); + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont); if (gpio_is_valid(lcd->gpio_backlight_on)) - gpio_set_value(lcd->gpio_backlight_on, intensity); + gpio_set_value_cansleep(lcd->gpio_backlight_on, intensity); if (lcd->kick_battery) lcd->kick_battery(); -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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