From: Frank Li <Frank.li@oss.nxp.com>
To: Daniel Byrne <daniel1.byrne@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>, Dave Jiang <dave.jiang@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>, Frank Li <Frank.Li@kernel.org>,
Vinicius Costa Gomes <vinicius.gomes@intel.com>,
Jonathan Corbet <corbet@lwn.net>,
Ludovic Desroches <ludovic.desroches@microchip.com>,
dmaengine@vger.kernel.org, linux-doc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] dmaengine: drop DMA_COMPLETION_NO_ORDER and DMA_OUT_OF_ORDER
Date: Mon, 19 Oct 2026 14:02:04 -0500 [thread overview]
Message-ID: <atZpLBovBBsSGHPq@SMW015318> (raw)
In-Reply-To: <20261019150632.4026424-4-daniel1.byrne@intel.com>
On Mon, Oct 19, 2026 at 08:06:32AM -0700, Daniel Byrne wrote:
> [You don't often get email from daniel1.byrne@intel.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> DMA_COMPLETION_NO_ORDER (commit 47ec7f09bc10 ("dmaengine: cookie bypass
> for out of order completion")) flagged devices whose completions can
> overtake submission order. On DSA this happens when a work queue (one
> dmaengine channel) belongs to a group that contains several engines.
> Per-channel cookie tracking gives wrong answers in this case, since
> dma_cookie_complete() moves the completed-cookie watermark past
> still-in-flight earlier descriptors, so cookie-order status can report
> DMA_COMPLETE for a running transfer. Clients were told to use
> callbacks only, dmatest refused polled mode, and DMA_OUT_OF_ORDER
> existed as the tx_status answer for such devices.
Thank you for such cleanup. But I have not understood what means. Does
DMA_OUT_OF_ORDER will never happen now?
Frank
prev parent reply other threads:[~2026-10-19 19:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-19 15:06 [PATCH 0/3] [PATCH 0/3] dmaengine: polled completion status for out-of-order providers Daniel Byrne
2026-10-19 15:06 ` [PATCH 1/3] dmaengine: add dmaengine_async_is_tx_complete() for channel status queries Daniel Byrne
2026-10-19 18:36 ` Frank Li
2026-10-19 15:06 ` [PATCH 2/3] dmaengine: idxd: generation-number transaction status Daniel Byrne
2026-10-19 18:53 ` Dave Jiang
2026-10-19 15:06 ` [PATCH 3/3] dmaengine: drop DMA_COMPLETION_NO_ORDER and DMA_OUT_OF_ORDER Daniel Byrne
2026-10-19 19:02 ` Frank Li [this message]
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