Re: [PATCH 1/1] usb: ulpi: ulpi_init should be used in subsys_initcall

["Lu, Baolu" <baolu.lu@linux.intel.com>]

On 05/21/2015 03:33 PM, Heikki Krogerus wrote:
> On Thu, May 21, 2015 at 01:40:43PM +0800, Lu Baolu wrote:
>> The intention of this change is to fix below kernel panic when
>> USB_ULPI_BUS was configured as buildin.
> That is actually incorrect. Having the bus build-in does not cause
> this panic..
>
>> [0.746856] kernel BUG at drivers/base/driver.c:153!
>> [0.752418] invalid opcode: 0000 [#1] PREEMPT SMP
>> [0.757804] Modules linked in:
>> [0.893985] Call Trace:
>> [0.896729]  [<ffffffff81870cb1>] ? ulpi_register_driver+0x21/0x30
>> [0.903654]  [<ffffffff823d5cac>] tusb1210_driver_init+0x10/0x12
>> [0.910386]  [<ffffffff81000318>] do_one_initcall+0xd8/0x200
>> [0.916729]  [<ffffffff8239b094>] kernel_init_freeable+0x196/0x21e
>> [0.923655]  [<ffffffff81affed0>] ? rest_init+0x90/0x90
>> [0.929509]  [<ffffffff81affede>] kernel_init+0xe/0xf0
>> [0.935266]  [<ffffffff81b0f442>] ret_from_fork+0x42/0x70
>> [0.941315]  [<ffffffff81affed0>] ? rest_init+0x90/0x90
> This happens if the PHY drivers are build-in. If the bus is build-in,
> but the drivers are modules, you are still fine.

I ever tried the config of bus "=y" and driver "=n". It results in
panic as well. The call trace looks like below.

1.058876]  [<ffffffff8165a6d2>] device_add+0x402/0x640
[1.064829]  [<ffffffff8165a92e>] device_register+0x1e/0x30
[1.071072]  [<ffffffff81870bdc>] ulpi_register_interface+0x14c/0x1f0
[1.078291]  [<ffffffff817c68d4>] dwc3_ulpi_init+0x24/0x60
[1.084437]  [<ffffffff817be052>] dwc3_probe+0x802/0x1650
[1.090487]  [<ffffffff8165fb54>] platform_drv_probe+0x34/0xa0
[1.097022]  [<ffffffff8165d9e9>] driver_probe_device+0x209/0x4b0
[1.103850]  [<ffffffff8165dc90>] ? driver_probe_device+0x4b0/0x4b0
[1.110871]  [<ffffffff8165dccb>] __device_attach+0x3b/0x40
[1.117114]  [<ffffffff8165b6d3>] bus_for_each_drv+0x63/0xa0
[1.123454]  [<ffffffff8165d778>] device_attach+0x98/0xb0
[1.129503]  [<ffffffff8165cb60>] bus_probe_device+0xa0/0xc0
[1.135843]  [<ffffffff8165a73f>] device_add+0x46f/0x640
[1.141799]  [<ffffffff81090fe0>] ? __insert_resource+0x60/0x150
[1.148530]  [<ffffffff8165f780>] platform_device_add+0xd0/0x2b0
[1.155260]  [<ffffffff817c7386>] dwc3_pci_probe+0xf6/0x2c0
[1.161505]  [<ffffffff8149d86c>] pci_device_probe+0x8c/0xf0
[1.167846]  [<ffffffff8165d9e9>] driver_probe_device+0x209/0x4b0
[1.174673]  [<ffffffff8165dd6b>] __driver_attach+0x9b/0xa0
[1.180917]  [<ffffffff8165dcd0>] ? __device_attach+0x40/0x40
[1.187354]  [<ffffffff8165b60b>] bus_for_each_dev+0x6b/0xb0
[1.193694]  [<ffffffff8165d2be>] driver_attach+0x1e/0x20
[1.199742]  [<ffffffff8165ce80>] bus_add_driver+0x180/0x250
[1.206086]  [<ffffffff823e453c>] ? 
ftrace_define_fields_dwc3_log_trb+0x126/0x126
[1.214474]  [<ffffffff8165e5d4>] driver_register+0x64/0xf0
[1.220718]  [<ffffffff8149c51b>] __pci_register_driver+0x4b/0x50
[1.227546]  [<ffffffff823e4555>] dwc3_pci_driver_init+0x19/0x1b
[1.234277]  [<ffffffff81000318>] do_one_initcall+0xd8/0x200
[1.240619]  [<ffffffff8239b094>] kernel_init_freeable+0x196/0x21e
[1.247545]  [<ffffffff81affbd0>] ? rest_init+0x90/0x90
[1.253399]  [<ffffffff81affbde>] kernel_init+0xe/0xf0
[1.259156]  [<ffffffff81b0f142>] ret_from_fork+0x42/0x70
[1.265205]  [<ffffffff81affbd0>] ? rest_init+0x90/0x90

>
> Maybe it would have been better to explain that this is addressing an
> issue with the execution sequence, and consider Sasha's patch as the
> actual fix for panic.

Fair enough. I will resend the patch.

>
>
> Thanks guys,
>

Thanks,
Baolu