Re: [PATCH for 4.12] Revert "pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip"

[Tony Lindgren <tony@atomide.com>]

* Brian Norris <briannorris@chromium.org> [170626 17:06]:
> So I agree that the above commit was problematic, and that you have
> fixed that in your patch ("PM / wakeirq: Convert to SRCU"). But I
> noticed there were other threads where people have complained about the
> $subject patch also causing problems with drivers that call
> disable_irq_nosync() from within an IRQ context. So I poked around with
> one such driver that calls disable_irq_nosync() from its ISR [1], and
> saw this:
> 
> [   14.524945] Bluetooth: : OOB Wake-on-BT configured at IRQ 56
> [   14.531657] usbcore: registered new interface driver btusb
> [   18.973886] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238
> [   18.987695] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0
> [   18.995282] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.12.0-rc6+ #1233
> [   19.002669] Hardware name: Google Kevin (DT)
> [   19.007435] Call trace:
> [   19.010171] [<ffffff8008089928>] dump_backtrace+0x0/0x24c
> [   19.016202] [<ffffff8008089b94>] show_stack+0x20/0x28
> [   19.021846] [<ffffff8008371270>] dump_stack+0x90/0xb0
> [   19.027488] [<ffffff80080cd2a0>] ___might_sleep+0x10c/0x124
> [   19.033713] [<ffffff80080cd330>] __might_sleep+0x78/0x88
> [   19.039647] [<ffffff800879e248>] mutex_lock+0x2c/0x64
> [   19.045291] [<ffffff80083ad578>] rockchip_irq_bus_lock+0x30/0x3c
> [   19.052003] [<ffffff80080f6c68>] __irq_get_desc_lock+0x78/0x98
> [   19.058519] [<ffffff80080f8e90>] __disable_irq_nosync+0x38/0x80
> [   19.065132] [<ffffff80080f8ef8>] disable_irq_nosync+0x20/0x2c
> [   19.071555] [<ffffff8000a99f58>] btusb_oob_wake_handler+0x4c/0x68 [btusb]

Hmm so how come drivers/bluetooth/btusb.c can't use the generic
dev_pm_set_dedicated_wake_irq()? Can you please take a look?

If there are issues remaining let's rather fix them so we can get rid
of the custom tinkering of wake-up events in the drivers.

Regards,

Tony