From: Bin Liu <b-liu@ti.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>,
dmaengine@vger.kernel.org, linux-usb@vger.kernel.org,
stable@vger.kernel.org
Subject: dma: cppi41: delete channel from pending list when stop channel
Date: Mon, 26 Nov 2018 07:47:38 -0600 [thread overview]
Message-ID: <20181126134738.GD27653@uda0271908> (raw)
Hi,
On Sat, Nov 24, 2018 at 07:58:03PM +0530, Vinod Koul wrote:
> On 12-11-18, 09:43, Bin Liu wrote:
> > The driver defines three states for a cppi channel.
> > - idle: .chan_busy == 0 && not in .pending list
> > - pending: .chan_busy == 0 && in .pending list
> > - busy: .chan_busy == 1 && not in .pending list
> >
> > There are cases in which the cppi channel could be in the pending state
> > when cppi41_dma_issue_pending() is called after cppi41_runtime_suspend()
> > is called.
> >
> > cppi41_stop_chan() has a bug for these cases to set channels to idle state.
> > It only checks the .chan_busy flag, but not the .pending list, then later
> > when cppi41_runtime_resume() is called the channels in .pending list will
> > be transitioned to busy state.
> >
> > Removing channels from the .pending list solves the problem.
>
> I would like some testing, given that intent is to go to stable.
> Peter..?
FYI, this cppi41 dma driver is *only* used by musb controller driver. In
the past I received multiple reports for this issue, but I wasn't able
to reproduce it using similar test cases. The only way I could trigger
the issue is to do system suspend/resume test on AM335x with a USB hub
attached to the usb host port. This issue only happens once in the very
*first* time suspend/resume test after reboot.
Regards,
-Bin.
next reply other threads:[~2018-11-26 13:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 13:47 Bin Liu [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-12-06 14:56 dma: cppi41: delete channel from pending list when stop channel Bin Liu
2018-12-05 8:32 Vinod Koul
2018-11-28 11:16 Peter Ujfalusi
2018-11-28 11:15 Peter Ujfalusi
2018-11-24 14:28 Vinod Koul
2018-11-12 15:46 Bin Liu
2018-11-12 15:43 Bin Liu
2018-11-12 15:40 Bin Liu
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