From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] PCI: Fixup the RTIT_BAR of Intel TH on Denverton
Date: Tue, 19 Sep 2017 20:27:08 +0300 [thread overview]
Message-ID: <87vaketx8z.fsf@ashishki-desk.ger.corp.intel.com> (raw)
In-Reply-To: <20170919165842.GA22312@bhelgaas-glaptop.roam.corp.google.com>
Bjorn Helgaas <helgaas@kernel.org> writes:
> Hi Alexander,
Hi Bjorn,
> On Tue, Sep 19, 2017 at 05:51:36PM +0300, Alexander Shishkin wrote:
>> On some intergrations of the Intel TH the reported size of RTIT_BAR
>
> s/intergrations/integrations/
Oops.
> What is "TH"? If there's a public spec for it, can you include a
> reference here?
Intel Trace Hub,
https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
There's an overview at Documentation/trace/intel_th.txt.
> I guess this is an erratum, since the device responds to more MMIO
> space than it advertises via the BAR. Can you include a reference to
> the published erratum?
There's no erratum at the moment, unfortunately.
>> doesn't match its actual size, which leads to overlaps with other
>> devices' resources.
>
> So I suppose the BIOS relies on the size advertised via the BAR,
> assigns it to be just below the XHCI space, and now both the TH and
> XHCI respond there? I assume this causes some sort of "unexpected
> response" error? Is there a bug report about this? What does it look
> like when a user hits this? I'm trying to make this fix discoverable
> to users who might trip over the problem.
When the intel_th pci device gets enabled (on modprobe, for example),
XHCI starts seeing 0xffffffff in its MMIO registers, which makes it go
xhci_hcd: xHCI host controller not responding, assume dead
xhci_hcd: xHC not responding in xhci_irq, assume controller is dead
xhci_hcd: HC died; cleaning up
followed by disappearance of keyboards and user's profound confusion.
I'll make sure to mention all this in the commit message.
>> For this reason, we need to resize the RTIT_BAR on Denverton where
>> it would overlap with XHCI MMIO space.
>>
>> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
>> Fixes: 5118ccd347 ("intel_th: pci: Add Denverton SOC support")
>
> Please use a 12-char SHA1.
Will do.
>> Cc: stable@vger.kernel.org
>
> I guess this is only applicable to v4.11+, since 5118ccd34780 appeared in
> v4.11-rc4?
Right, my git-send-email keeps trying to CC "# v4.11+" if I leave it in the
Cc: stable line.
Regards,
--
Alex
prev parent reply other threads:[~2017-09-19 17:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 14:51 Alexander Shishkin
2017-09-19 16:58 ` Bjorn Helgaas
2017-09-19 17:27 ` Alexander Shishkin [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87vaketx8z.fsf@ashishki-desk.ger.corp.intel.com \
--to=alexander.shishkin@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=helgaas@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®