imx serial driver commit breaks system boot on i.MX6 boards

imx serial driver commit breaks system boot on i.MX6 boards

[Clemens Gruber]

Hi,

the imx serial driver is broken after the "serial: imx: remove unbalanced
clk_prepare" commit 9e7b399d6528eac33a6fbfceb2b92af209c3454d.

My i.MX6Q boards do not boot anymore due to aforementioned commit.

The error looks like this:
...
[    0.510764] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 21, base_baud = 5000000) is a IMX
[    0.513005] 21e8000.serial: ttymxc1 at MMIO 0x21e8000 (irq = 286, base_baud = 5000000) is a IMX
[    1.295637] console [ttymxc1] enabled
[    1.295662] BUG: scheduling while atomic: swapper/0/1/0x00000002
[    1.295668] 4 locks held by swapper/0/1:
[    1.295693]  #0:  (&dev->mutex){......}, at: [<802e8fbc>] __driver_attach+0x48/0x98
[    1.295712]  #1:  (&dev->mutex){......}, at: [<802e8fcc>] __driver_attach+0x58/0x98
[    1.295737]  #2:  (port_mutex){+.+.+.}, at: [<802dad8c>] uart_add_one_port+0x78/0x4c8
[    1.295756]  #3:  (&port->mutex){+.+.+.}, at: [<802dad98>] uart_add_one_port+0x84/0x4c8
[    1.295762] Modules linked in:
[    1.295765] irq event stamp: 236325
[    1.295779] hardirqs last  enabled at (236325): [<80081fdc>] vprintk_emit+0x23c/0x624
[    1.295788] hardirqs last disabled at (236324): [<80081df0>] vprintk_emit+0x50/0x624
[    1.295806] softirqs last  enabled at (236300): [<800353f4>] __do_softirq+0x228/0x2ac
[    1.295816] softirqs last disabled at (236293): [<800357ac>] irq_exit+0xd8/0x114
[    1.295823] Preemption disabled at:[<  (null)>]   (null)
[    1.295825] 
[    1.295835] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.3.0-rc4-00037-g9751522 #41
[    1.295839] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[    1.295868] [<80017a0c>] (unwind_backtrace) from [<80013fa4>] (show_stack+0x10/0x14)
[    1.295888] [<80013fa4>] (show_stack) from [<8027bd94>] (dump_stack+0x84/0xc4)
[    1.295908] [<8027bd94>] (dump_stack) from [<80055b7c>] (__schedule_bug+0x7c/0xdc)
[    1.295931] [<80055b7c>] (__schedule_bug) from [<80548bf4>] (__schedule+0x4dc/0x5f8)
[    1.295942] [<80548bf4>] (__schedule) from [<80548dc4>] (schedule+0x48/0xa8)
[    1.295956] [<80548dc4>] (schedule) from [<8054dd6c>] (schedule_hrtimeout_range_clock+0xb4/0x138)
[    1.295971] [<8054dd6c>] (schedule_hrtimeout_range_clock) from [<8054d874>] (usleep_range+0x68/0x84)
[    1.295994] [<8054d874>] (usleep_range) from [<803e95d8>] (clk_pllv3_wait_lock+0x78/0xac)
[    1.296008] [<803e95d8>] (clk_pllv3_wait_lock) from [<803e2c88>] (clk_core_prepare+0x98/0xbc)
[    1.296019] [<803e2c88>] (clk_core_prepare) from [<803e2c68>] (clk_core_prepare+0x78/0xbc)
...

After that it shows the same error, starting again with "BUG: scheduling while
atomic.."

A revert patch from Fabio Estevam was sent on Aug 18th of 2015.

Is there a reason why that revert patch has not been merged yet?
Hopefully this will be fixed before the 4.3 release.

Thanks,
Clemens

imx serial driver commit breaks system boot on i.MX6 boards

[Fabio Estevam]

On Wed, Oct 7, 2015 at 11:39 AM, Clemens Gruber
<clemens.gruber@pqgruber.com> wrote:

> A revert patch from Fabio Estevam was sent on Aug 18th of 2015.
>
> Is there a reason why that revert patch has not been merged yet?
> Hopefully this will be fixed before the 4.3 release.

Already reverted in Greg's tree:
https://git.kernel.org/cgit/linux/kernel/git/gregkh/tty.git/commit/?h=tty-linus&id=0c727a42043f79db210cdde0366f9137b9c6bf5a

Should be available in 4.3-rc5.

imx serial driver commit breaks system boot on i.MX6 boards

[Clemens Gruber]

On Wed, Oct 07, 2015 at 11:42:07AM -0300, Fabio Estevam wrote:
> On Wed, Oct 7, 2015 at 11:39 AM, Clemens Gruber
> <clemens.gruber@pqgruber.com> wrote:
> 
> > A revert patch from Fabio Estevam was sent on Aug 18th of 2015.
> >
> > Is there a reason why that revert patch has not been merged yet?
> > Hopefully this will be fixed before the 4.3 release.
> 
> Already reverted in Greg's tree:
> https://git.kernel.org/cgit/linux/kernel/git/gregkh/tty.git/commit/?h=tty-linus&id=0c727a42043f79db210cdde0366f9137b9c6bf5a
> 
> Should be available in 4.3-rc5.

Awesome, thanks!