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Date: Thu, 9 May 2024 15:49:24 +0200
From: Christoph Hellwig <hch@lst.de>
To: Steven Price <steven.price@arm.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>,
	Christoph Hellwig <hch@lst.de>, Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Magnus Karlsson <magnus.karlsson@intel.com>,
	nex.sw.ncis.osdt.itp.upstreaming@intel.com, bpf@vger.kernel.org,
	netdev@vger.kernel.org, iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 2/7] dma: avoid redundant calls for sync operations
Message-ID: <20240509134924.GA13607@lst.de>
References: <20240507112026.1803778-1-aleksander.lobakin@intel.com> <20240507112026.1803778-3-aleksander.lobakin@intel.com> <010686f5-3049-46a1-8230-7752a1b433ff@arm.com>
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On Thu, May 09, 2024 at 02:43:52PM +0100, Steven Price wrote:
> The specific drivers are "rockchip-drm" and "rk_gmac-dwmac". Is it a
> requirement that all drivers engaging in DMA should call dma_set_mask()
> - and therefore this has uncovered a bug in those drivers. Or is the
> assumption that all drivers call dma_set_mask() faulty?

That was the assumption behind the code, but the assumption is wrong.
Alex is working on a fix.