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

[Heikki Krogerus]

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.

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.


Thanks guys,

-- 
heikki
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