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From: Christoph Hellwig <hch@infradead.org>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Yue Hu" <huyue2@yulong.com>,
	"Michał Nazarewicz" <mina86@mina86.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Dmitry Vyukov" <dvyukov@google.com>,
	etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-mm@kvack.org, kernel@pengutronix.de,
	patchwork-lst@pengutronix.de
Subject: Re: [PATCH 1/2] mm: cma: export functions to get CMA base and size
Date: Wed, 29 May 2019 23:26:44 -0700	[thread overview]
Message-ID: <20190530062644.GA20133@infradead.org> (raw)
In-Reply-To: <20190529104312.27835-1-l.stach@pengutronix.de>

On Wed, May 29, 2019 at 12:43:11PM +0200, Lucas Stach wrote:
> Make them usable in modules. Some drivers want to know where their
> device CMA area is located to make better decisions about the DMA
> programming.

NAK.  This is very much a layering violation.  At very least you'd
need to wire this up through the DMA API and deal with dma_addr_t
addresses instead of physical addresses, which are opaque to DMA
using drivers.  But even for that we'd need a really good rationale.


      parent reply	other threads:[~2019-05-30  6:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 10:43 Lucas Stach
2019-05-29 10:43 ` [PATCH 2/2] drm/etnaviv: use CMA area to compute linear window offset if possible Lucas Stach
2021-05-03  7:46   ` Primoz Fiser
2019-05-30  6:26 ` Christoph Hellwig [this message]

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