From: Bjorn Helgaas <helgaas@kernel.org>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: Christopher Covington <cov@codeaurora.org>,
Taku Izumi <izumi.taku@jp.fujitsu.com>,
linux-pci@vger.kernel.org, timur@codeaurora.org, jcm@redhat.com,
Bjorn Helgaas <bhelgaas@google.com>,
Yijing Wang <wangyijing@huawei.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI/AER: enable SERR# forwarding and role-based error reporting
Date: Thu, 3 Dec 2015 11:48:53 -0600 [thread overview]
Message-ID: <20151203174853.GC17565@localhost> (raw)
In-Reply-To: <565E76E9.1020307@codeaurora.org>
On Tue, Dec 01, 2015 at 11:43:21PM -0500, Sinan Kaya wrote:
> On 12/1/2015 6:07 PM, Bjorn Helgaas wrote:
> > On Tue, Dec 01, 2015 at 03:08:48PM -0500, Sinan Kaya wrote:
> >> For instance, what happens after hotplug insertion. Will anybody set
> >> these bits? We need some kernel support for some PCIe features to
> >> reconfigure the hardware.
> >
> > ACPI systems that support hotplug may supply _HPP or _HPX methods. If
> > _HPP or _HPX indicates that SERR# forwarding should be enabled, Linux
> > does enable it for hot-added devices (and I think we now do it for all
> > devices at boot, too). That would explain how this could work on ACPI
> > systems today.
>
> Are we sure about this? The name of the field in HPP is "Enable SERR".
> Will this also enable SERR# forwarding?
I *think* so. In program_hpp_type0(), if hpp->enable_serr is set, we
turn on PCI_COMMAND_SERR. For bridges, we also turn on
PCI_BRIDGE_CTL_SERR, which enables SERR# forwarding. Of course, I
don't have a machine I'm testing this on; I'm just reading the code.
> I do have _HPP in ACPI with SERR enabled but I do not have HPX. I rely
> on the hardware defaults for which errors to be enabled and masked etc.
> So, I don't need HPX.
Huh. If you have _HPP with "Enable SERR" set, I wonder why the
pci_configure_device() path isn't turning on PCI_COMMAND_SERR and
PCI_BRIDGE_CTL_SERR for you. Can you instrument that path and see
what's going on? I reworked that recently, and my *intent* was that
we apply _HPP & _HPX settings to every device we enumerate, not just
hot-added ones. If that isn't happening, I'd like to know about it.
Bjorn
prev parent reply other threads:[~2015-12-03 17:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-26 21:25 [PATCH] PCI/AER: enable SERR# forwarding and role-based error reporting Sinan Kaya
2015-12-01 18:51 ` Bjorn Helgaas
2015-12-01 19:21 ` Christopher Covington
2015-12-01 20:08 ` Sinan Kaya
2015-12-01 23:07 ` Bjorn Helgaas
2015-12-02 4:43 ` Sinan Kaya
2015-12-02 16:13 ` Sinan Kaya
2015-12-03 17:48 ` Bjorn Helgaas [this message]
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