From: Kalle Valo <kvalo@codeaurora.org>
To: Ganapathi Bhat <gbhat@marvell.com>
Cc: <linux-wireless@vger.kernel.org>,
Brian Norris <briannorris@chromium.org>,
Cathy Luo <cluo@marvell.com>, Xinming Hu <huxm@marvell.com>,
Zhiyuan Yang <yangzy@marvell.com>, James Cao <jcao@marvell.com>,
Mangesh Malusare <mmangesh@marvell.com>,
Shrenik Shikhare <shrenik@marvell.com>,
Ganapathi Bhat <gbhat@marvell.com>
Subject: Re: [1/2] mwifiex: schedule rx_work on RX interrupt for USB
Date: Thu, 25 Jan 2018 07:10:53 +0000 (UTC) [thread overview]
Message-ID: <20180125071053.29F1C6032C@smtp.codeaurora.org> (raw)
In-Reply-To: <1516633497-6584-2-git-send-email-gbhat@marvell.com>
Ganapathi Bhat <gbhat@marvell.com> wrote:
> From: Shrenik Shikhare <shrenik@marvell.com>
>
> There is race for data_received flag between main thread and
> RX data interrupt(mwifiex_usb_rx_complete()):
> 1. USB received an RX data interrupt, set data_received flag
> 2. main thread checks data_received, if set queues rx_work
> 3. rx worker thread independently start processing rx_data_q
> 4. rx work exits (once rx_data_q is empty)
> 5. main thread resets the data_received flag(after #2)
> 6. Now at the corner case there will be high RX data interrupts
> between #4 and #5
> 7. Driver stops submitting URBs to firmware, once rx_pending
> exceeds HIGH_RX_PENDING
> 8. The flag data_received(cleared in #5) will remain unset since
> there will be no interrupts from firmware to set it(after #7)
>
> Above scenario causes RX stall in driver, which will finally
> result in command/TX timeouts in firmware.
>
> As a fix, queue rx_work directly in mwifiex_usb_rx_complete()
> callback, instead in the main thread. This removes dependency
> of RX processing on data_received flag.
>
> Signed-off-by: Cathy Luo <cluo@marvell.com>
> Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
Brian, did you have a chance to review these two?
--
https://patchwork.kernel.org/patch/10178731/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2018-01-25 7:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-22 15:04 [PATCH 0/2] mwifiex: fix RX data stall issue on USB interface Ganapathi Bhat
2018-01-22 15:04 ` [PATCH 1/2] mwifiex: schedule rx_work on RX interrupt for USB Ganapathi Bhat
2018-01-25 7:10 ` Kalle Valo [this message]
[not found] ` <20180125071052.E370660A4E@smtp.codeaurora.org>
2018-01-25 18:32 ` [1/2] " Brian Norris
2018-01-25 18:59 ` [PATCH 1/2] " Brian Norris
2018-01-29 7:21 ` [EXT] " Ganapathi Bhat
2018-01-22 15:04 ` [PATCH 2/2] mwifiex: use more_rx_task_flag to avoid USB RX stall Ganapathi Bhat
2018-01-25 7:12 ` [2/2] " Kalle Valo
2018-01-25 7:13 ` Kalle Valo
2018-01-25 10:02 ` [EXT] " Ganapathi Bhat
[not found] ` <20180125071202.0F39560A60@smtp.codeaurora.org>
2018-01-25 9:59 ` Ganapathi Bhat
2018-01-25 12:59 ` Kalle Valo
2018-01-25 13:26 ` Ganapathi Bhat
2018-01-25 18:33 ` Brian Norris
2018-01-29 7:17 ` Ganapathi Bhat
2018-01-29 7:19 ` Ganapathi Bhat
2018-01-29 22:08 ` Brian Norris
2018-01-30 15:25 ` Ganapathi Bhat
2018-01-31 6:59 ` Ganapathi Bhat
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