From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 1/2] ARM: dma-mapping: Don't use outer_flush_range when the L2C is coherent
Date: Tue, 29 Sep 2015 19:30:31 +0200 [thread overview]
Message-ID: <20150929193031.72bbebe8@free-electrons.com> (raw)
In-Reply-To: <20150929171054.GN21513@n2100.arm.linux.org.uk>
Hello Russell,
On Tue, 29 Sep 2015 18:10:54 +0100, Russell King - ARM Linux wrote:
> > In the current kernel implementation, the outer cache flush range
> > operation is triggered by the dma_alloc function.
> > This operation can be take place during runtime and in some
> > circumstances may lead to the PCIe/PL310 deadlock on Armada 375/38x
> > SoCs.
>
> I wonder if that's what's causing the sporadic lockups I'm seeing on
> 38x with a SATA PCIe card - it happens at a very specific point during
> boot while initialising the SATA card, right down to the kernel message
> character that it stops at.
It might very well be the case. If there's enough PCIe traffic and a
PL310 cache maintenance operation happening at the same time, the
system will lockup. I'm a bit surprised that just the initialization of
the PCIe card generates enough traffic to trigger the deadlock, but
maybe I'm underestimating the problem.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
linux-arm-kernel@lists.infradead.org,
Maxime Ripard <maxime.ripard@free-electrons.com>,
Boris BREZILLON <boris.brezillon@free-electrons.com>,
Lior Amsalem <alior@marvell.com>,
Tawfik Bayouk <tawfik@marvell.com>,
Nadav Haklai <nadavh@marvell.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v4 1/2] ARM: dma-mapping: Don't use outer_flush_range when the L2C is coherent
Date: Tue, 29 Sep 2015 19:30:31 +0200 [thread overview]
Message-ID: <20150929193031.72bbebe8@free-electrons.com> (raw)
In-Reply-To: <20150929171054.GN21513@n2100.arm.linux.org.uk>
Hello Russell,
On Tue, 29 Sep 2015 18:10:54 +0100, Russell King - ARM Linux wrote:
> > In the current kernel implementation, the outer cache flush range
> > operation is triggered by the dma_alloc function.
> > This operation can be take place during runtime and in some
> > circumstances may lead to the PCIe/PL310 deadlock on Armada 375/38x
> > SoCs.
>
> I wonder if that's what's causing the sporadic lockups I'm seeing on
> 38x with a SATA PCIe card - it happens at a very specific point during
> boot while initialising the SATA card, right down to the kernel message
> character that it stops at.
It might very well be the case. If there's enough PCIe traffic and a
PL310 cache maintenance operation happening at the same time, the
system will lockup. I'm a bit surprised that just the initialization of
the PCIe card generates enough traffic to trigger the deadlock, but
maybe I'm underestimating the problem.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2015-09-29 17:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-29 16:50 [PATCH v4 0/2] Fix dma mapping when the cache is coherent Gregory CLEMENT
2015-09-29 16:50 ` [PATCH v4 1/2] ARM: dma-mapping: Don't use outer_flush_range when the L2C " Gregory CLEMENT
2015-09-29 16:50 ` Gregory CLEMENT
2015-09-29 17:10 ` Russell King - ARM Linux
2015-09-29 17:10 ` Russell King - ARM Linux
2015-09-29 17:30 ` Thomas Petazzoni [this message]
2015-09-29 17:30 ` Thomas Petazzoni
2015-09-29 17:48 ` Russell King - ARM Linux
2015-09-29 17:48 ` Russell King - ARM Linux
2015-09-29 17:55 ` Thomas Petazzoni
2015-09-29 17:55 ` Thomas Petazzoni
2015-09-30 9:28 ` Gregory CLEMENT
2015-09-30 9:28 ` Gregory CLEMENT
2015-09-29 16:50 ` [PATCH v4 2/2] ARM: dma-mapping: Fix the coherent case when iommu is used Gregory CLEMENT
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