Hi All, Can we land this patch upstream? Feel free to add my tested-by.
Thanks. Regards, Shirish S -----Original Message----- From: S, Shirish <shiris...@amd.com> Sent: Wednesday, July 1, 2020 12:15 PM To: Tony Lindgren <t...@atomide.com>; Sergey Senozhatsky <sergey.senozhat...@gmail.com> Cc: Petr Mladek <pmla...@suse.com>; Andy Shevchenko <andy.shevche...@gmail.com>; Raul Rangel <rran...@google.com>; Sergey Senozhatsky <sergey.senozhatsky.w...@gmail.com>; linux-kernel <linux-kernel@vger.kernel.org>; Greg Kroah-Hartman <gre...@linuxfoundation.org>; Andy Shevchenko <andriy.shevche...@linux.intel.com>; k...@linutronix.de; S, Shirish <shiris...@amd.com>; Peter Zijlstra <pet...@infradead.org>; John Ogness <john.ogn...@linutronix.de>; Steven Rostedt <rost...@goodmis.org> Subject: Re: UART/TTY console deadlock On 6/30/2020 11:32 PM, Tony Lindgren wrote: > * Sergey Senozhatsky <sergey.senozhat...@gmail.com> [200630 13:06]: >> On (20/06/30 14:22), Petr Mladek wrote: > ... > >>>>>> @@ -2284,8 +2289,6 @@ int serial8250_do_startup(struct uart_port *port) >>>>>> * allow register changes to become visible. >>>>>> */ >>>>>> spin_lock_irqsave(&port->lock, flags); >>>>>> - if (up->port.irqflags & IRQF_SHARED) >>>>>> - disable_irq_nosync(port->irq); >>>>>> >>>>>> wait_for_xmitr(up, UART_LSR_THRE); >>>>>> serial_port_out_sync(port, UART_IER, UART_IER_THRI); @@ >>>>>> -2297,9 +2300,9 @@ int serial8250_do_startup(struct uart_port *port) >>>>>> iir = serial_port_in(port, UART_IIR); >>>>>> serial_port_out(port, UART_IER, 0); >>>>>> >>>>>> - if (port->irqflags & IRQF_SHARED) >>>>>> - enable_irq(port->irq); >>>>>> spin_unlock_irqrestore(&port->lock, flags); >>>>>> + if (irq_shared) >>>>>> + enable_irq(port->irq); >>>>>> >>>>>> /* >>>>>> * If the interrupt is not reasserted, or we otherwise >>>>> I think that it might be safe but I am not 100% sure, sigh. >>>> Yeah, I'm not 100%, but I'd give it a try. >>> I do not feel brave enough to ack it today. But I am all for trying >>> it if anyone more familiar with the code is fine with it. >> I see. Well, I suppose we need Ack-s from tty/serial/8250 maintainers. >> I would not be very happy if _only_ printk people Ack the patch. FWIW, the lockdep trace is not seen anymore with the patch applied. Regards, Shirish S > This conditional disable for irq_shared does not look nice to me from > the other device point of view :) > > Would it be possible to just set up te dummy interrupt handler for the > startup, then change it back afterwards? See for example > omap8250_no_handle_irq(). > > The other device for irq_shared should be capable of dealing with > spurious interrupts if it's shared. > > Regards, > > Tony -- Regards, Shirish S
