linux-kernel - Re: [PATCH] dma: pl330: Add support for DMA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 14 May 2014 17:29:05 +0530
From:	Jassi Brar <jassisinghbrar@...il.com>
To:	Tushar Behera <tushar.behera@...aro.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	dmaengine@...r.kernel.org, Vinod Koul <vinod.koul@...el.com>,
	Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command

On Wed, May 14, 2014 at 8:53 AM, Tushar Behera <tushar.behera@...aro.org> wrote:
> While playing back audio, pmc_dmaengine requests the DMA channel to
> stop DMA transmission through DMA_PAUSE command.
>
> Currently PL330 driver doesn't support DMA pause command, leaving
> the DMA state inconsistent when the system resumes. Instead, it would
> be better to terminate the DMA transfer during suspend and restart
> again during resume.
>
> Tested with audio playback across a suspend-resume cycle.
>
What is pmc_dmaengine? How does DMA_PAUSE help, when there is no DMA_RESUME?

DMA_PAUSE means freezing the transfer, not dropping it. DMA_RESUME
then moves the transfer again from that point. Clubbing PAUSE with
TERMINATE is plain wrong.  Sorry.

Regards
Jassi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/