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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	qi.wang@intel.com, yong.y.wang@intel.com, joel.clark@intel.com,
	kok.howg.ewe@intel.com
Subject: Re: [PATCH] pch_uart: Fix dma channel unallocated issue
Date: Mon, 9 Apr 2012 10:44:05 -0700	[thread overview]
Message-ID: <20120409174405.GA25990@kroah.com> (raw)
In-Reply-To: <1332842162-26113-1-git-send-email-tomoya.rohm@gmail.com>

On Tue, Mar 27, 2012 at 06:56:02PM +0900, Tomoya MORINAGA wrote:
> This driver anticipates pch_uart_verify_port() is not called
> during installation.
> However, actually pch_uart_verify_port() is called during
> installation.
> As a result, memory access violation occurs like below.
> 
> 0. initial value: use_dma=0
> 1. starup()
>     - dma channel is not allocated because use_dma=0
> 2. pch_uart_verify_port()
>     - Set use_dma=1
> 3. UART processing acts DMA mode because use_dma=1
>      - memory access violation occurs!
> 
> This patch fixes the issue.
> 
> Solution:
> Whenever pch_uart_verify_port() is called and then
> dma channel is not allocated, the channel should be allocated.
> 
> Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
> ---
>  drivers/tty/serial/pch_uart.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)

This patch does not apply to 3.4-rc2, so I can not apply it, sorry.

Care to redo it?

greg k-h

  reply	other threads:[~2012-04-09 17:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-27  9:56 [PATCH] pch_uart: Fix dma channel unallocated issue Tomoya MORINAGA
2012-04-09 17:44 ` Greg Kroah-Hartman [this message]
2012-04-10  1:26   ` Tomoya MORINAGA
2012-04-10 14:41     ` Greg Kroah-Hartman

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