linux-kernel - Re: [PATCH] dma: tegra: implement suspend/resume callbacks

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]

Message-ID: <5182B396.308@wwwdotorg.org>
Date:	Thu, 02 May 2013 12:42:30 -0600
From:	Stephen Warren <swarren@...dotorg.org>
To:	Vinod Koul <vinod.koul@...el.com>
CC:	Laxman Dewangan <ldewangan@...dia.com>, djbw@...com,
	linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dma: tegra: implement suspend/resume callbacks

On 04/30/2013 04:30 AM, Vinod Koul wrote:
> On Wed, Apr 24, 2013 at 03:24:27PM +0530, Laxman Dewangan wrote:
>> Implement suspend/resume callbacks to store APB DMA channel's
>> register on suspend and restore APB DMA channel's register on
>> resume.
...
> You dont seem to handle suspend when DMA is active? Otherwise looks fine.
> Stephen, you okay with this patch?

Yes, I think this looks fine. Sorry for the slow response; I was on
vacation.

One question though: Laxman mentioned that DMA clients were responsible
for suspending their DMA accesses themselves. Does the dmaengine core
define the semantics here; are DMA drivers supposed to handle suspend
with active DMAs, or should DMA clients suspend their DMA accesses
themselves as Laxman suggests? If the latter, I wonder if we actually
need to save/restore all the registers, since after resume, a new DMA
access would be started in all cases, which would then reprogram the HW.
--
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/