On 11:05-20141204, Guenter Roeck wrote: > On Thu, Dec 04, 2014 at 10:58:47AM -0600, Nishanth Menon wrote: > > Certain I2C based GPIO expanders could be used in sleepable context, > > this results in: > > [ 115.890569] ------------[ cut here ]------------ > > [ 115.895422] WARNING: CPU: 0 PID: 1115 at drivers/gpio/gpiolib.c:1370 gpiod_set_raw_value+0x40/0x4c() > > [ 115.905024] Modules linked in: > > [ 115.908229] CPU: 0 PID: 1115 Comm: sh Tainted: G W 3.18.0-rc7-next-20141203-dirty #1 > > [ 115.917461] Hardware name: Generic DRA74X (Flattened Device Tree) > > [ 115.923876] [<c0015368>] (unwind_backtrace) from [<c00119f4>] (show_stack+0x10/0x14) > > [ 115.932013] [<c00119f4>] (show_stack) from [<c05b78e8>] (dump_stack+0x78/0x94) > > [ 115.939594] [<c05b78e8>] (dump_stack) from [<c003de28>] (warn_slowpath_common+0x7c/0xb4) > > [ 115.948094] [<c003de28>] (warn_slowpath_common) from [<c003de7c>] (warn_slowpath_null+0x1c/0x24) > > [ 115.957315] [<c003de7c>] (warn_slowpath_null) from [<c03461e8>] (gpiod_set_raw_value+0x40/0x4c) > > [ 115.966457] [<c03461e8>] (gpiod_set_raw_value) from [<c04866f4>] (set_fan_speed+0x4c/0x64) > > [ 115.975145] [<c04866f4>] (set_fan_speed) from [<c04868a8>] (set_rpm+0x98/0xac) > > [ 115.982742] [<c04868a8>] (set_rpm) from [<c039fb4c>] (dev_attr_store+0x18/0x24) > > [ 115.990426] [<c039fb4c>] (dev_attr_store) from [<c01b0a28>] (sysfs_kf_write+0x4c/0x50) > > [ 115.998742] [<c01b0a28>] (sysfs_kf_write) from [<c01afe1c>] (kernfs_fop_write+0xbc/0x19c) > > [ 116.007333] [<c01afe1c>] (kernfs_fop_write) from [<c0148cc4>] (vfs_write+0xb0/0x1a0) > > [ 116.015461] [<c0148cc4>] (vfs_write) from [<c0148fbc>] (SyS_write+0x44/0x84) > > [ 116.022881] [<c0148fbc>] (SyS_write) from [<c000e5c0>] (ret_fast_syscall+0x0/0x48) > > [ 116.030833] ---[ end trace 3a0b636123acab82 ]--- > > > > So, switch over to sleepable GPIO operations as there is no mandatory > > need for non-sleepable gpio operations in the fan driver. > > > > This allows the fan driver to be used with i2c based gpio expanders such > > as palmas_gpio. > > > > Signed-off-by: Nishanth Menon <nm@xxxxxx> > > Applied to hwmon-next. Do we need this in older kernels ? I have'nt had a need for it till recently.. in terms of the sleepable get/set, it seems to have been introduced with commit 7560fa60fcdcdb0da662f6a9fad9064b554ef46c Author: David Brownell <david-b@xxxxxxxxxxx> Date: Tue Mar 4 14:28:27 2008 -0800 gpio: <linux/gpio.h> and "no GPIO support here" stubs Guessing no one needed it so far.. so probably future should be good enough, I think.. -- Regards, Nishanth Menon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
