From: Marek Vasut <marek.vasut@gmail.com>
To: Robin Murphy <robin.murphy@arm.com>,
Andrew Murray <andrew.murray@arm.com>
Cc: Simon Horman <horms@verge.net.au>,
linux-pci@vger.kernel.org,
Marek Vasut <marek.vasut+renesas@gmail.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Wolfram Sang <wsa@the-dreams.de>,
linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH V3 2/3] PCI: rcar: Do not abort on too many inbound dma-ranges
Date: Sun, 22 Dec 2019 08:46:24 +0100 [thread overview]
Message-ID: <ddb1295c-dbee-d965-0278-52d8b8937940@gmail.com> (raw)
In-Reply-To: <82c69634-ffb5-0b20-2254-55e5cfbef035@arm.com>
On 11/18/19 7:42 PM, Robin Murphy wrote:
[...]
>>> Despite the good intentions here, it doesn't seem like dma-ranges is
>>> designed for this purpose and as the hardware has limited ranges it will
>>> only be best-effort.
>> So what other options do we have ?
>
> If you really want to sacrifice DMA efficiency for a perceived increase
> in theoretical robustness by setting very conservative windows,
That really means configuring the hardware correctly.
> then
> ultimately it's your choice, go ahead. It's just that you *need* to make
> that choice in the bootloader, not in Linux. If Linux gets passed
> dma-ranges that aren't actually reflected by the hardware, such that
> this patch is needed, then it *will* go wrong eventually, and you'll
> only get an "I told you so" from me.
>
> The bootloader knows what platform it's running on, so it has no excuse
> for emitting more ranges than there are available windows on that platform.
So basically the conclusion is to limit the amount of DMA ranges added
into the DT and be done with it ?
--
Best regards,
Marek Vasut
next prev parent reply other threads:[~2019-12-22 14:32 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 17:57 [PATCH V3 1/3] PCI: rcar: Move the inbound index check marek.vasut
2019-08-09 17:57 ` [PATCH V3 2/3] PCI: rcar: Do not abort on too many inbound dma-ranges marek.vasut
2019-08-16 13:23 ` Simon Horman
2019-08-16 13:28 ` Marek Vasut
2019-08-16 13:38 ` Simon Horman
2019-08-16 17:41 ` Marek Vasut
2019-10-21 10:18 ` Andrew Murray
2019-10-26 18:03 ` Marek Vasut
2019-10-26 20:36 ` Andrew Murray
2019-10-26 21:06 ` Andrew Murray
2019-11-06 23:37 ` Marek Vasut
2019-11-07 14:19 ` Andrew Murray
2019-11-16 15:48 ` Marek Vasut
2019-11-18 18:42 ` Robin Murphy
2019-12-22 7:46 ` Marek Vasut [this message]
2019-10-16 15:00 ` Lorenzo Pieralisi
2019-10-16 15:10 ` Marek Vasut
2019-10-16 15:26 ` Lorenzo Pieralisi
2019-10-16 15:29 ` Marek Vasut
2019-10-16 16:18 ` Lorenzo Pieralisi
2019-10-16 18:12 ` Rob Herring
2019-10-16 18:17 ` Marek Vasut
2019-10-16 20:25 ` Rob Herring
2019-10-16 21:15 ` Marek Vasut
2019-10-16 22:26 ` Rob Herring
2019-10-16 22:33 ` Marek Vasut
2019-10-17 7:06 ` Geert Uytterhoeven
2019-10-17 10:55 ` Marek Vasut
2019-10-17 13:06 ` Robin Murphy
2019-10-17 14:00 ` Marek Vasut
2019-10-17 14:36 ` Rob Herring
2019-10-17 15:01 ` Marek Vasut
2019-10-18 9:53 ` Lorenzo Pieralisi
2019-10-18 12:22 ` Marek Vasut
2019-10-18 12:53 ` Robin Murphy
2019-10-18 14:26 ` Marek Vasut
2019-10-18 15:44 ` Robin Murphy
2019-10-18 16:44 ` Marek Vasut
2019-10-18 17:35 ` Robin Murphy
2019-10-18 18:44 ` Marek Vasut
2019-10-21 8:32 ` Geert Uytterhoeven
2019-11-19 12:10 ` Robin Murphy
2019-10-18 10:06 ` Andrew Murray
2019-10-18 10:17 ` Geert Uytterhoeven
2019-10-18 11:40 ` Andrew Murray
2019-08-09 17:57 ` [PATCH V3 3/3] PCI: rcar: Recalculate inbound range alignment for each controller entry marek.vasut
2019-10-21 10:39 ` Andrew Murray
2019-08-16 10:52 ` [PATCH V3 1/3] PCI: rcar: Move the inbound index check Lorenzo Pieralisi
2019-08-16 10:59 ` Marek Vasut
2019-08-16 11:10 ` Lorenzo Pieralisi
2019-10-15 20:14 ` Marek Vasut
2019-10-21 10:11 ` Andrew Murray
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