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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ilya Zykov <ilya@ilyx.ru>
Cc: Andrew McGregor <andrew.mcgregor@alliedtelesis.co.nz>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Cox <alan@linux.intel.com>,
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org
Subject: Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).
Date: Wed, 21 Nov 2012 21:30:37 +0000	[thread overview]
Message-ID: <20121121213037.154306da@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <50AD43DB.4030800@ilyx.ru>

> Function reset_buffer_flags() also invoked during the
> ioctl(...,TCFLSH,..). At the time of request we can have full buffers
> and throttled driver too. If we don't unthrottle driver, we can get
> forever throttled driver, because after request, we will have
> empty buffers and throttled driver and there is no place to unthrottle driver.
> It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
> and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.


So instead of revertng it why not just fix it ? Just add an argument to
the reset_buffer_flags function to indicate if unthrottling is permitted.

Alan

  reply	other threads:[~2012-11-22 18:47 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-21 21:12 [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..) Ilya Zykov
2012-11-21 21:30 ` Alan Cox [this message]
2012-11-21 21:39   ` Ilya Zykov
2012-11-22  0:47     ` andrew mcgregor
2012-11-22  4:29       ` Ilya Zykov
2012-11-22  5:25         ` andrew mcgregor
2012-11-22  6:35           ` Ilya Zykov
2012-11-22  6:03         ` Ilya Zykov
2012-11-22  6:16           ` Ilya Zykov
2012-11-21 21:55   ` Ilya Zykov
2012-11-27  6:14 [PATCH v4] " Ilya Zykov
2012-11-27 17:24 ` Greg Kroah-Hartman
2012-11-27 18:46   ` Ilya Zykov
2012-11-27 19:32     ` Alan Cox
2013-01-16  9:07       ` [PATCH] " Ilya Zykov

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