From: Vinod Koul <vkoul@kernel.org>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Paul Burton <paul.burton@mips.com>,
od@zcrc.me, dmaengine@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] dmaengine: dma-jz4780: Break descriptor chains on JZ4740
Date: Thu, 25 Jul 2019 18:58:09 +0530 [thread overview]
Message-ID: <20190725132809.GW12733@vkoul-mobl.Dlink> (raw)
In-Reply-To: <20190714215504.10877-1-paul@crapouillou.net>
On 14-07-19, 17:55, Paul Cercueil wrote:
> The current driver works perfectly fine on every generation of the
> JZ47xx SoCs, except on the JZ4740.
>
> There, when hardware descriptors are chained together (with the LINK
> bit set), the next descriptor isn't automatically fetched as it should -
> instead, an interrupt is raised, even if the TIE bit (Transfer Interrupt
> Enable) bit is cleared. When it happens, the DMA transfer seems to be
> stopped (it doesn't chain), and it's uncertain how many bytes have
> actually been transferred.
>
> Until somebody smarter than me can figure out how to make chained
> descriptors work on the JZ4740, we now disable chained descriptors on
> that particular SoC.
Applied, thanks
--
~Vinod
prev parent reply other threads:[~2019-07-25 13:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-14 21:55 [PATCH v2] dmaengine: dma-jz4780: Break descriptor chains on JZ4740 Paul Cercueil
2019-07-25 13:28 ` Vinod Koul [this message]
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