From: Mason <slash.tmp@free.fr>
To: Russell King - ARM Linux <linux@armlinux.org.uk>,
Bjorn Helgaas <helgaas@kernel.org>
Cc: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <marc.zyngier@arm.com>,
linux-pci <linux-pci@vger.kernel.org>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v9 2/3] PCI: Add tango PCIe host bridge support
Date: Wed, 5 Jul 2017 01:59:55 +0200 [thread overview]
Message-ID: <0cd65cda-9a3d-8c1b-1ee9-c48f63959140@free.fr> (raw)
In-Reply-To: <20170703181128.GD4902@n2100.armlinux.org.uk>
On 03/07/2017 20:11, Russell King - ARM Linux wrote:
> I don't think there's an easy solution to this problem - and I'm not
> sure that stop_machine() can be made to work in this path (which
> needs a process context). I have a suspicion that the Sigma Designs
> PCI implementation is just soo insane that it's never going to work
> reliably in a multi-SoC kernel without introducing severe performance
> issues for everyone else.
If I remember correctly, this is the second HW block from
tango that has been deemed "too insane for Linux".
The first one was the DMA engine, which doesn't interrupt
when a transfer is done, but when a new transfer may be
programmed. (Though there is a simple work-around for
this one, if we give up command pipelining.)
Do larger SoC vendors have HW devs working closely with
Linux devs, to avoid these design bloopers?
Regards.
next prev parent reply other threads:[~2017-07-05 0:00 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-20 8:12 [PATCH v9 0/3] Tango PCIe controller support Marc Gonzalez
2017-06-20 8:14 ` [PATCH v9 1/3] PCI: Add DT binding for tango PCIe controller Marc Gonzalez
2017-06-20 8:17 ` [PATCH v9 2/3] PCI: Add tango PCIe host bridge support Marc Gonzalez
2017-07-02 23:18 ` Bjorn Helgaas
2017-07-03 9:35 ` Ard Biesheuvel
2017-07-03 13:27 ` Bjorn Helgaas
2017-07-04 6:58 ` Jisheng Zhang
2017-07-04 7:16 ` Jisheng Zhang
2017-07-04 8:02 ` Ard Biesheuvel
2017-07-04 8:19 ` Jisheng Zhang
2017-07-04 9:38 ` Ard Biesheuvel
2017-07-05 13:53 ` Joao Pinto
2017-07-03 9:54 ` Marc Gonzalez
2017-07-03 13:13 ` Marc Gonzalez
2017-07-03 15:30 ` Marc Gonzalez
2017-07-04 7:09 ` Peter Zijlstra
2017-07-04 13:08 ` Mason
2017-07-04 14:27 ` Peter Zijlstra
2017-07-04 15:18 ` Mason
2017-07-03 13:40 ` Bjorn Helgaas
2017-07-03 14:34 ` Marc Gonzalez
2017-07-04 15:58 ` Bjorn Helgaas
2017-07-04 23:42 ` Mason
2017-07-03 18:11 ` Russell King - ARM Linux
2017-07-03 18:44 ` Ard Biesheuvel
2017-07-04 15:15 ` Bjorn Helgaas
2017-07-04 18:17 ` Russell King - ARM Linux
2017-07-04 23:59 ` Mason [this message]
2017-07-05 5:21 ` Greg Kroah-Hartman
2017-07-05 12:33 ` Mark Brown
2017-06-20 8:18 ` [PATCH v9 3/3] PCI: Add tango MSI controller support Marc Gonzalez
2017-07-04 20:24 ` [PATCH v9 0/3] Tango PCIe " Bjorn Helgaas
2017-07-04 22:55 ` Mason
2017-07-05 18:03 ` Bjorn Helgaas
2017-07-05 20:39 ` Mason
2017-07-05 21:34 ` Bjorn Helgaas
2017-07-05 21:59 ` Mason
2017-07-06 3:39 ` Bjorn Helgaas
2017-07-06 12:26 ` Mason
2017-07-06 12:40 ` Marc Zyngier
2017-07-06 19:46 ` Bjorn Helgaas
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