From: Larry Finger <Larry.Finger@lwfinger.net>
To: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
"chaoming_li@realsil.com.cn" <chaoming_li@realsil.com.cn>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "kvalo@codeaurora.org" <kvalo@codeaurora.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Ravikiran Gummaluri <rgummal@xilinx.com>
Subject: Re: [PATCH] rtlwifi: rtl8192x: Enabling and disabling hardware interrupts after enabling local irq flags
Date: Fri, 20 Jan 2017 10:30:05 -0600 [thread overview]
Message-ID: <07fff87e-4dc2-f7b1-76f1-263be2410905@lwfinger.net> (raw)
In-Reply-To: <8520D5D51A55D047800579B094147198263CA86D@XAP-PVEXMBX02.xlnx.xilinx.com>
On 01/20/2017 08:14 AM, Bharat Kumar Gogada wrote:
> > On 01/19/2017 04:14 AM, Bharat Kumar Gogada wrote:
>>> -Realtek 8192CE chipset maintains local irq flags after enabling/disabling
>>> hardware interrupts.
>>> -Hardware interrupts are enabled before enabling the local irq
>>> flags(these flags are being checked in interrupt handler),
>>> leading to race condition on some RP, where the irq line between
>>> bridge and GIC goes high at ASSERT_INTx and goes low only
>>> at DEASSERT_INTx. In this kind of RP by the time ASSERT_INTx is seen
>>> irq_enable flag is still set to false, resulting in continuous
>>> interrupts seen by CPU as DEASSERT_INTx cannot be sent since
>>> flag is still false and making CPU stall.
>>> -Changing the sequence of setting these irq flags.
>>>
>>> Signed-off-by: Bharat Kumar Gogada <bharatku@xilinx.com>
>>> ---
>>
>> This patch should be enhanced with the smb_xx() calls as suggested by by Lino.
>>
>> The subject should be changed. I would suggest something like "rtlwifi:
>> rtl8192ce: Prevent race condition when enabling interrupts", as it explains the
>> condition you are preventing.
>>
>> The other PCI drivers also have the same problem. Do you want to prepare the
>> patches, or should I do it?
>>
> Thanks Larry. Please send out the patches adding the above enhancements suggested by Lino.
I have prepared a patch fixing all the drivers. By the way, what CPU hardware
showed this problem?
Larry
next prev parent reply other threads:[~2017-01-20 16:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-19 10:14 [PATCH] rtlwifi: rtl8192x: Enabling and disabling hardware interrupts after enabling local irq flags Bharat Kumar Gogada
2017-01-19 14:35 ` Lino Sanfilippo
2017-01-19 18:08 ` Larry Finger
2017-01-19 22:13 ` Lino Sanfilippo
2017-01-20 2:41 ` Larry Finger
2017-01-20 11:14 ` Lino Sanfilippo
2017-01-20 14:14 ` Bharat Kumar Gogada
2017-01-20 16:30 ` Larry Finger [this message]
2017-01-24 10:03 ` Bharat Kumar Gogada
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