From: Vinod Koul <vinod.koul@intel.com>
To: Sekhar Nori <nsekhar@ti.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
DMA Engine Mailing List <dmaengine@vger.kernel.org>,
Linux DaVinci Mailing List
<davinci-linux-open-source@linux.davincidsp.com>,
Jon Ringle <jringle@gridpoint.com>,
Alexander Holler <holler@ahsoftware.de>,
Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
Joel Fernandes <joelf@ti.com>
Subject: Re: [PATCH 1/1] dma: edma: fix incorrect SG list handling
Date: Mon, 14 Apr 2014 14:27:46 +0530 [thread overview]
Message-ID: <20140414085746.GG32284@intel.com> (raw)
In-Reply-To: <534B9CCF.1070904@ti.com>
On Mon, Apr 14, 2014 at 02:01:11PM +0530, Sekhar Nori wrote:
> Vinod,
>
> On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote:
> > The code to handle any length SG lists calls edma_resume()
> > even before edma_start() is called. This is incorrect
> > because edma_resume() enables edma events on the channel
> > after which CPU (in edma_start) cannot clear posted
> > events by writing to ECR (per the EDMA user's guide).
> >
> > Because of this EDMA transfers fail to start if due
> > to some reason there is a pending EDMA event registered
> > even before EDMA transfers are started. This can happen if
> > an EDMA event is a byproduct of device initialization.
> >
> > Fix this by calling edma_resume() only if it is not the
> > first batch of MAX_NR_SG elements.
> >
> > Without this patch, MMC/SD fails to function on DA850 EVM
> > with DMA. The behaviour is triggered by specific IP and
> > this can explain why the issue was not reported before
> > (example with MMC/SD on AM335x).
> >
> > Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card.
> >
> > Cc: stable@vger.kernel.org # v3.12.x+
> > Cc: Joel Fernandes <joelf@ti.com>
> > Acked-by: Joel Fernandes <joelf@ti.com>
> > Tested-by: Jon Ringle <jringle@gridpoint.com>
> > Tested-by: Alexander Holler <holler@ahsoftware.de>
> > Reported-by: Jon Ringle <jringle@gridpoint.com>
> > Signed-off-by: Sekhar Nori <nsekhar@ti.com>
>
> Looks like this patch is not in mainline still?
Sorry looks like I have missed sending the email. I had applied it last week and
today rebased after rc1. It would be part of rc2...
--
~Vinod
>
> Thanks,
> Sekhar
--
next prev parent reply other threads:[~2014-04-14 9:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 5:55 [PATCH 1/1] dma: edma: fix incorrect SG list handling Sekhar Nori
2014-04-14 8:31 ` Sekhar Nori
2014-04-14 8:57 ` Vinod Koul [this message]
2014-04-14 9:09 ` Sekhar Nori
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140414085746.GG32284@intel.com \
--to=vinod.koul@intel.com \
--cc=dan.j.williams@intel.com \
--cc=davinci-linux-open-source@linux.davincidsp.com \
--cc=dmaengine@vger.kernel.org \
--cc=holler@ahsoftware.de \
--cc=joelf@ti.com \
--cc=jringle@gridpoint.com \
--cc=linux-omap@vger.kernel.org \
--cc=nsekhar@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).