On Mon, Nov 09, 2020 at 05:14:03PM +0800, Fugang Duan wrote:
> For below code, there has chance to cause deadlock in SMP system:
> Thread 1:
> clk_enable_lock();
> pr_info("debug message");
> clk_enable_unlock(flags);
flags?
>
> Thread 2:
> imx_uart_console_write()
> clk_enable()
> clk_enable_lock();
>
> Thread 1:
> Acuired clk enable_lock -> printk -> console_trylock_spinning
> Thread 2:
> console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock
>
> So the patch is to keep console port clocks always on like
> other console drivers.
>
> Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx>
Depending on how old this problem is, identifying the commit that
introduces the problem (and noting it in a Fixes: line) would be good.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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