Re: [PATCH] tty: add Moxa Smartio MUE serial driver

From	Mathieu OTHACEHE <m.othacehe@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] tty: add Moxa Smartio MUE serial driver
Date	2016-02-03 20:00 +0100
Message-ID	<qYaOK-5HS-9@gated-at.bofh.it> (permalink)
References	<qXtqp-8iB-1@gated-at.bofh.it> <qXu38-mK-19@gated-at.bofh.it>
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Thank you for your comments. I'll come up with v2 soon but, I have
a question about this point :

> > +		/* clear Rx/Tx FIFO's */
> > +		for (i = 0; i < reset_cnt; i++) {
> > +			iowrite8((UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT),
> > +				 info->ioaddr + UART_FCR);
> > +			msleep(sleep_interval);
> 
> No can do - you have a spinlock held while you are tring to sleep. I'm
> not btw clear that you actually need the lock. The tty_port layer ensures
> activate/shutdown don't cross or get duplicated. The only protection you
> might need is versus interrupts, and in that case you could free the IRQ
> up and claim it in activate/shutdown.

So is it possible to replace spin_lock_irqsave/restore by local_irq_save/restore
in activate/shutdown to protect versus interrupts ?

And is it allowed to call msleep while holding local_irq_save ?

Thank you,

Mathieu

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Re: [PATCH] tty: add Moxa Smartio MUE serial driver One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-02-01 22:20 +0100
  Re: [PATCH] tty: add Moxa Smartio MUE serial driver Mathieu OTHACEHE <m.othacehe@gmail.com> - 2016-02-03 20:00 +0100

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