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Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled

From Sören Brinkmann <soren.brinkmann@xilinx.com>
Newsgroups linux.kernel
Subject Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled
Date 2015-12-05 23:20 +0100
Message-ID <qCtlo-6PY-5@gated-at.bofh.it> (permalink)
References <qxt2F-5Ri-3@gated-at.bofh.it> <qxtcl-6aY-3@gated-at.bofh.it> <qCp85-44S-3@gated-at.bofh.it>
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On Sat, 2015-12-05 at 12:43PM -0500, Peter Hurley wrote:
> On 11/21/2015 09:59 PM, Soren Brinkmann wrote:
> > Ignore RX-related interrupts if RX is not enabled.
> 
> This doesn't look like a safe approach; fast-forward a couple of years and
> some is trying to add some feature but can't figure out why no data is
> arriving...
> 
> What is this trying to solve?

I definitely saw two kinds of lock ups. One was on the TX side, that the
system tried to print with the transmitter disabled.

The other on the RX side. I don't recall the details, but the system was
stuck in some RX-related function waiting for data while the receiver
was disabled. I think my explanation was that some IRQ condition becomes
true and is dispatched to the RX handler even though the receiver isn't
enabled.
I guess a better way for solving this would be to disable the IRQs that
call the RX handler when the receiver is disabled.

	Sören
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Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX  is enabled Peter Hurley <peter@hurleysoftware.com> - 2015-12-05 18:50 +0100
  Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX  is enabled Sören Brinkmann <soren.brinkmann@xilinx.com> - 2015-12-05 23:20 +0100

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