From: Bjorn Helgaas <bhelgaas@google.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Alan Stern" <stern@rowland.harvard.edu>,
"AceLan Kao" <acelan.kao@canonical.com>,
linux-pci@vger.kernel.org, "洪(Alex)茂耕" <alex.hung@canonical.com>
Subject: Re: [PATCH] PCI: Quirk for ASUS S3 issue
Date: Thu, 5 Jul 2012 16:39:18 -0600 [thread overview]
Message-ID: <CAErSpo6AJEdCem2oAv6z0wGiGTZSLQAs5sJN+_rN1d9uqyT7BQ@mail.gmail.com> (raw)
In-Reply-To: <201207060000.51762.rjw@sisk.pl>
On Thu, Jul 5, 2012 at 4:00 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Thursday, July 05, 2012, Alan Stern wrote:
>> On Thu, 5 Jul 2012, Bjorn Helgaas wrote:
>>
>> > I wish we knew more about what's really going on here. I looked
>> > through the bug reports AceLan dug up, and I don't get the feeling
>> > that anybody really has a grand unified theory about why Windows works
>> > but Linux doesn't. But I'm willing to apply one of these patches if
>> > you and/or Alan sign off on it.
>>
>> His description seems to make sense, even if it may not be complete.
>>
>> Windows sets the COMMAND register to 0 before suspending, so it doesn't
>> trigger the BIOS bus. Linux doesn't, so the BIOS tries to quiesce the
>> EHCI controller. This involves doing various MMIO accesses, which of
>> course don't work if the controller is already in D3.
Should we clear the COMMAND register for more than just EHCI devices?
It seems like known differences from Windows are just waiting to bite
us.
I like your patch and explanation for how this can cause a hang...
that helps make sense of things.
>> For obvious reasons, I'm in favor of my two-line change over AceLan's
>> new PCI quirk. So far there have been positive responses from a few
>> volunteers testing the patch.
>
> The two-liner is good enough, I think, and tested. We can always add a quirk
> based on it in the future.
Cool, do you want to send me a patch with Signed-off-by, etc?
next prev parent reply other threads:[~2012-07-05 22:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-03 8:55 [PATCH] PCI: Quirk for ASUS S3 issue AceLan Kao
2012-07-03 16:16 ` Bjorn Helgaas
2012-07-03 20:17 ` Alan Stern
2012-07-04 2:03 ` AceLan Kao
2012-07-04 18:47 ` Alan Stern
2012-07-04 21:14 ` Rafael J. Wysocki
2012-07-05 18:17 ` Bjorn Helgaas
2012-07-05 21:33 ` Alan Stern
2012-07-05 22:00 ` Rafael J. Wysocki
2012-07-05 22:39 ` Bjorn Helgaas [this message]
2012-07-06 2:01 ` Alan Stern
2012-07-04 8:34 AceLan Kao
2012-07-04 8:39 ` AceLan Kao
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=CAErSpo6AJEdCem2oAv6z0wGiGTZSLQAs5sJN+_rN1d9uqyT7BQ@mail.gmail.com \
--to=bhelgaas@google.com \
--cc=acelan.kao@canonical.com \
--cc=alex.hung@canonical.com \
--cc=linux-pci@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=stern@rowland.harvard.edu \
/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;
as well as URLs for NNTP newsgroup(s).