From: Mason <slash.tmp@free.fr>
To: Robin Murphy <robin.murphy@arm.com>,
linux-pci <linux-pci@vger.kernel.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
David Laight <david.laight@aculab.com>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
Phuong Nguyen <phuong_nguyen@sigmadesigns.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
netdev <netdev@vger.kernel.org>,
Tim Harvey <tharvey@gateworks.com>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: Legacy features in PCI Express devices
Date: Mon, 13 Mar 2017 18:39:55 +0100 [thread overview]
Message-ID: <58fb1386-fa94-dde3-b361-597f9486fa41@free.fr> (raw)
In-Reply-To: <96b57ba5-641d-46c8-6ba0-cee2c0613a6f@arm.com>
On 13/03/2017 18:12, Robin Murphy wrote:
> On 13/03/17 16:10, Mason wrote:
>
>> There are two revisions of our PCI Express controller.
>>
>> Rev 1 did not support the following features:
>>
>> 1) legacy PCI interrupt delivery (INTx signals)
>> 2) I/O address space
>>
>> Internally, someone stated that such missing support would prevent
>> some PCIe cards from working with our controller.
>>
>> Are there really modern PCIe cards that require 1) and/or 2)
>> to function?
>>
>> Can someone provide examples of such cards, so that I may test them
>> on both revisions?
>>
>> I was told to check ath9k-based cards. Any other examples?
>>
>> Looking around, I came across this thread:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/418254.html
>> "i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity"
>>
>> IIUC, although some PCIe boards do support MSI, the driver might not
>> put in the work to use that infrastructure, and instead reverts to
>> legacy interrupts. (So it is a SW issue, in a sense.)
>
> Secondary to that category is endpoints which nominally support MSI, but
> in a way which is unreliable or otherwise broken. My experience shows
> that the Silicon Image SiI 3132 (as integrated on ARM Juno boards, but
> seemingly also relatively common on 'generic' 2-port SATA cards) falls
> into that category - using the command-line parameter to force MSIs
> instead of legacy interrupts leads to the the machine barely reaching
> userspace before something goes horribly wrong:
Do drivers typically support *both* MSI and INTx?
Specifically, would the xhci driver support both?
If I remove MSI support from my kernel, I might be able to test
legacy interrupt support that way, right?
Regards.
WARNING: multiple messages have this Message-ID (diff)
From: slash.tmp@free.fr (Mason)
To: linux-arm-kernel@lists.infradead.org
Subject: Legacy features in PCI Express devices
Date: Mon, 13 Mar 2017 18:39:55 +0100 [thread overview]
Message-ID: <58fb1386-fa94-dde3-b361-597f9486fa41@free.fr> (raw)
In-Reply-To: <96b57ba5-641d-46c8-6ba0-cee2c0613a6f@arm.com>
On 13/03/2017 18:12, Robin Murphy wrote:
> On 13/03/17 16:10, Mason wrote:
>
>> There are two revisions of our PCI Express controller.
>>
>> Rev 1 did not support the following features:
>>
>> 1) legacy PCI interrupt delivery (INTx signals)
>> 2) I/O address space
>>
>> Internally, someone stated that such missing support would prevent
>> some PCIe cards from working with our controller.
>>
>> Are there really modern PCIe cards that require 1) and/or 2)
>> to function?
>>
>> Can someone provide examples of such cards, so that I may test them
>> on both revisions?
>>
>> I was told to check ath9k-based cards. Any other examples?
>>
>> Looking around, I came across this thread:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/418254.html
>> "i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity"
>>
>> IIUC, although some PCIe boards do support MSI, the driver might not
>> put in the work to use that infrastructure, and instead reverts to
>> legacy interrupts. (So it is a SW issue, in a sense.)
>
> Secondary to that category is endpoints which nominally support MSI, but
> in a way which is unreliable or otherwise broken. My experience shows
> that the Silicon Image SiI 3132 (as integrated on ARM Juno boards, but
> seemingly also relatively common on 'generic' 2-port SATA cards) falls
> into that category - using the command-line parameter to force MSIs
> instead of legacy interrupts leads to the the machine barely reaching
> userspace before something goes horribly wrong:
Do drivers typically support *both* MSI and INTx?
Specifically, would the xhci driver support both?
If I remove MSI support from my kernel, I might be able to test
legacy interrupt support that way, right?
Regards.
next prev parent reply other threads:[~2017-03-13 17:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-13 16:10 Legacy features in PCI Express devices Mason
2017-03-13 16:10 ` Mason
2017-03-13 11:08 ` Greg
2017-03-13 11:08 ` Greg
2017-03-13 11:08 ` Greg
2017-03-13 17:12 ` Robin Murphy
2017-03-13 17:12 ` Robin Murphy
2017-03-13 17:39 ` Mason [this message]
2017-03-13 17:39 ` Mason
2017-03-13 17:55 ` Robin Murphy
2017-03-13 17:55 ` Robin Murphy
2017-03-13 17:24 ` David Daney
2017-03-13 17:24 ` David Daney
2017-03-13 18:55 ` Bjorn Helgaas
2017-03-13 18:55 ` Bjorn Helgaas
2017-03-13 18:55 ` Bjorn Helgaas
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